Quality craftsmen to the retail jewellery trade
Hardness 6.5 / RI 1.530-1.540 / SG 2.60-2.64
Colours: All colours but mostly reddish-brown, yellow, white & blue.
Agate was highly valued as a talisman or amulet in the ancient times. It was said to quench thirst and protect from fever. Persian magicians used agate to divert the storms. A famous collection of two to four thousand agate bowls which was accumulated by Mithradates, king of Pontus, shows the enthusiasm with which agate was regarded.
Agate bowls were also popular in the Byzantine Empire. Collecting agate bowls became quite common among European royalty during the Renaissance and many museums in Europe, including the Louvre, have spectacular examples.
The mining of agate in the Nahe River valley in Germany which was already documented in 1497 gave rise to the cutting centre of Idar-Oberstein, Germany. Originally, the river was used to power the grinding wheels. When the Nahe agate deposit was exhausted in the nineteenth century, Idar cutters started to develop the agate deposits of Brazil, which also sparked exploration and discovery of Brazil's rich deposits of amethyst, citrine, tourmaline, topaz, and other gemstones.
Although the small town of Idar-Oberstein is still known for the finest agate carving in the world, today Idar imports a huge range of other gem materials from around the world for cutting and carving in Germany and Asia.
Cameo master carvers and modern lapidary artists flourish along with rough dealers who scour the world for the latest gem discoveries for export. And the entire industry sprung from the taste for agate bowls and ornaments during the Renaissance! Maybe agate is also a powerful talisman for success in international trade!
Hardness 8.5 / RI 1.745-1.780 / SG 3.71-3.75
Colours: Colour change from green in daylight to red in incandescent light, most dramatic colour change is best.
This rare gemstone is named after the Russian tsar Alexander II (1818-1881), the very first crystals having been discovered in April 1834 in the emerald mines near the Tokovaya River in the Urals. The discovery was made on the day the future tsar came of age. Although alexandrite is a relatively young gemstone, it certainly has a noble history. Since it shows both red and green, the principal colours of old Imperial Russia, it inevitably became the national stone of tsarist Russia.
Beautiful alexandrite in top quality, however, is very rare indeed and hardly ever used in modern jewellery. In antique Russian jewellery you may come across it with a little luck, since Russian master jewellers loved this stone. Tiffany’s master gemmologist George Frederick Kunz (1856-1932) was also fascinated by alexandrite, and the jeweller’s firm produced some beautiful series of rings and platinum ensembles at the end of the 19th and beginning of the 20th century. Smaller alexandrites were occasionally also used in Victorian jewellery from England.
The magic of changing colours
The most sensational feature about this stone, however, is its surprising ability to change its colour. Green or bluish-green in daylight, alexandrite turns a soft shade of red, purplish-red or raspberry red in incandescent light. This unique optical characteristic makes it one of the most valuable gemstones of all, especially in fine qualities.
Alexandrite is very scarce: this is due to its chemical composition. It is basically a chrysoberyl, a mineral consisting of colourless or yellow transparent chrysoberyl, chrysoberyl cat’s eye and colour-changing alexandrite (also in cat’s eye varieties). It differs from other chrysoberyls in that it not only contains iron and titanium, but also chromium as a major impurity. And it is this very element which accounts for the spectacular colour change. Rarely, vanadium may also play a part. According to CIBJO nomenclature, only chrysoberyls displaying a distinct change of colour may be termed alexandrite.
Like many other gemstones, alexandrite emerged millions of years ago in a metamorphic environment. But unlike many others, its formation required specific geological conditions. The chemical elements beryllium (a major constituent in chrysoberyl) and chromium (the colouring agent in alexandrite) have contrasting chemical characteristics and do not as a rule occur together, usually being found in contrasting rock types. Not only has Nature brought these contrasting rock types into contact with each other, but a lack of the chemical element silica (the second most common element in the Earth's crust) is also required to prevent the growth of emerald. This geological scenario has occurred only rarely in the Earth's history and, as a result, alexandrite crystals are very scarce indeed.
Hardness 7 / RI 1.544-1.553 / SG 2.65-2.66
Colours: Shades of violet / purple.
"Stone of spirituality and contentment". Amethyst bestows stability, strength, invigoration, and peace, the peace being the perfect peace, which was present prior to birth. It is "warm and cuddly" as well as regal and ruling. It has been used to encourage and support sobriety. It is an excellent stone for one who is attempting to find freedom from addictive personalities (oneself or another). It has calming, strong, protective qualities, healing, divine lone and inspiration. It also enhances one's psychic abilities.
Purple has long been considered a royal colour so it is not surprising that amethyst has been so much in demand during history. Fine amethysts are featured in the British Crown Jewels and were also a favourite of Catherine the Great and Egyptian royalty. Amethyst, transparent purple quartz, is the most important quartz variety used in jewellery.
Amethyst ranges in colour from pale lilac to deep purple. The pale colours are sometimes called "Rose de France" and can be seen set in Victorian jewellery. The deep colours are the most valuable, particularly a rich purple with rose flashes. Amethyst is mined in Brazil, Uruguay, Bolivia, India and Argentina, as well as in Zambia, Namibia and other African countries.
Generally, amethyst from South America tends to be available in larger sizes than African amethyst but amethyst from Africa has the reputation for having better, more saturated, colour in small sizes. Very dark amethyst, mostly in small sizes, is also mined in Australia.
Amethyst is available in a wide range of calibrated sizes and shapes, including many fancy shapes. Large fine stones may be sold in free sizes but generally amethyst is cut in standardized dimensions.
Hardness 7.5-8 / RI 1.564-1.596 / SG 2.68-2.74
Colours: Light blue to dark blue & blue-green.
"Say you're sorry, give your spouse this gem and promise that it will never, ever, happen again"
Aquamarine was also said to have a soothing influence on land, especially on married couples. Its power to help husbands and wives work out their differences and ensure a long and happy marriage makes it a good anniversary gift. Aquamarine also protects against the wiles of the devil.
A dream of aquamarine means that you will meet new friends. Aquamarine, the "gem of the sea", derives its name from "sea water". The reference is obvious: aqua sparkles like the sea and its colour is pale to medium blue, sometimes with a slight hint of green. Aquamarine is the birthstone for March. Aquamarine is found in Brazil, Zambia, Mozambique, Angola, Nigeria, and other countries.
Aquamarine is always in a pastel blue but the darker the colour, the more valued it is. Connoisseurs also prefer a pure blue, with no green in it. If you prefer a greenish tinge, you will find that these stones are less expensive.
This is a durable and lively gemstone that is appropriate for all jewellery uses. Its pale fire is flattering to most skin tones
Hardness 7 / RI 1.544-1.553 / SG 2.65-2.66
Colours: Shades of yellow to golden brown.
Citrine is one of the most affordable gemstones, thanks to the durability and availability of this golden quartz. Named from the French name for lemon, "citron," many citrines have a juicy lemon colour.
In ancient times, citrine was carried as a protection against snake venom and evil thoughts. Although the darker, orange colours of citrine, sometimes called Madeira citrine after the colour of the wine, has generally been the most valued colour, in modern times, many people prefer the bright lemony shades which mix better with pastel colours.
Citrine is generally more inexpensive than amethyst and is also available in a wide range of calibrated sizes and shapes, including very large sizes.
Sometimes you will hear citrine referred to as topaz quartz, which is incorrect. This name was used in the past in reference to the colour, which is sometimes similar to the colour of topaz. Since topaz is a separate mineral, this type of name can be confusing and should not be used. However, citrine is considered an alternative to topaz as the birthstone for November.
Most citrine is mined in Brazil. Supply of citrine is good from the Brazilian state of Rio Grande do Sul, particularly from the Serra mine, which is producing 300 kilos of hammered goods a month. The Iraâ mine produces an additional 100 kilos a month of hammered goods.
Since most citrine on the market started its life as amethyst which was heated to turn its colour to gold, citrine jewellery, as well as amethyst jewellery, should be kept away from prolonged exposure to strong light or heat. With this precaution, citrine jewellery will last for many generations.
Hardness 10 / RI 2.417-2.419 / SG 3.5-3.53
Colours: Colourless, shades of yellow, shades of pink, brown. (rarely green, blue, reddish & black).
Diamonds have been at the heart of myth and legend since their discovery. Medieval knights wore them uncut on their armour in the belief that they could make a person invincible, a myth no doubt related to the stone's hardness. There are legends of a diamond that could reveal the guilt or innocence of a person. Diamonds could also drive away the devil.
Almost universally, diamonds have been associated with virtue, purity, strength, wealth, power, and love. So it was a small jump for diamonds to become the modern symbol of love - diamond wedding rings have been popular for hundreds of years. They were believed to ensure fidelity and strengthen emotional bonds. Today, they are the preferred gift for all manner of romantic occasions.
Hardness 7.5-8 / RI 1.565-1.602 / SG 2.67-2.78
Colours: Light to dark green & yellowish-green.Info: The most precious of the beryl group named from the Greek ‘’smaragdos’ meaning ‘green stone’. Only the finest are transparent, inclusion free and fine colour. Is brittle and sensitive, must be treated carefully when making jewellery.
Emerald is the birthstone for May, the month of springtime romance, and the anniversary gemstone for the twentieth year of marriage, the perfect emblem of an enduring love.
Because the rich green colour of emerald is the colour of spring, the ancients prized it as the gemstone symbolizing love and rebirth. Treasured for at least 4,000 years by different cultures all around the world, emerald is said to quicken the intelligence as well as the heart. Legend gives its owner the gift of eloquence.
The Mughals of India, including Shah Jahan, the builder of the Taj Mahal, loved emeralds so much they inscribed them with sacred text and wore them as talismans. Some of these sacred stones, called Mughal emeralds, can still be seen in museums and collections today.
Today scientists tell us that the human eye is more sensitive to the colour green than to any other. Perhaps that is why green is so soothing to the eye, and why the colour green seems to complement every other colour: think of the beauty of a garden.
Spring can also be seen in the network of inclusions in the depth of the emerald that the French call the "jardin," or "garden," because it resembles foliage. The inclusions are like a fingerprint, giving each emerald a distinct personality. The extreme rarity of transparent emerald is why emeralds can be more valuable than diamonds.
Emeralds are cut in Jaipur, India and Tel-Aviv, Israel as well as in the mining countries. Emerald is one of the most difficult gemstones to cut because of the high value of the rough stone and the many inclusions found in crystals. Small changes in orientation can make a large difference in the final appearance of the gem. Skilled craftsmen who specialize in cutting emerald can be found in cities around the world for jewellers who insist on having stones perfected for the optimum brilliance and vibrancy.
As you might expect from gems that have been known to spend centuries at the bottom of the ocean and then return to sell for hundreds of thousands of dollars at auctions, emeralds are durable gemstones with a hardness of 7.5 to 8. However, emeralds with many inclusions should be treated with some care and be protected from blows. With a little care, your emerald will no doubt be treasured by your descendants thousands of years in the future! Although many people consider Colombia to be the source of the best emeralds, country of origin is never a guarantee of quality. Even the best mine produces mostly low quality gemstones because good qualities are very rare! Fine emeralds also come from Zambia, Brazil, Zimbabwe, Pakistan, Afghanistan, Madagascar, Nigeria, Russia and other countries, so don't be afraid to choose the emerald that looks better to you.
Hardness 5.5-6.5 / RI 1.37-1.52 / SG 1.98-2.5
Colours: Red,Deep to light orange to yellow.
Fire opals are unique in the lush world of the opals. They were already admired as symbols of the most fervent love in ancient times, in India and in the ancient Persian kingdom, and among the peoples of Central America and the Amerindians. It was believed that a gem that bubbled over with vivacity to such an extent as the fire opal could only have been created in the waters of paradise. The Mayas and Aztecs loved this gemstone and liked to use it in mosaics and for ritualistic purposes. They called it quetzalitzlipyollitli, the 'stone of the bird of paradise'. Yet one day, the gemstone knowledge of Mexico's natives, which had been handed down from generation to generation, somehow sank into oblivion for a long time ..... until, in or around the year 1835, the fiery treasures hidden in the Mexican highlands were remembered, and work was gradually begun on the systematic mining of the places where they had been found. Today, the fire opal is regarded as the national gemstone of that country.
It is in Mexico that the most significant fire opal deposits in the world lie. Rock strata containing opals run through the Mexican highlands, with their many extinct volcanoes. With a few exceptions, the gemstone, which lies hidden in cavities and crevices, is extracted in open-cast mines, the work giving rise to impressive canyons with walls up to 60 metres high and labyrinthine passages which wind their way through the mining areas.
Sometimes, these orange-red gemstones are also found in other countries, in Honduras or Guatemala, in the USA, Canada, Australia, Ethiopia and Turkey, but these are mostly sites of little or no economic significance. With Brazil it is a different matter. Several years ago, in an agate mine near Campos Borges in the South Brazilian State of Rio Grande do Sul, fire opals coloured yellow to orange were discovered. They distinguish themselves by their beautiful colour, often with slight clouding, but without play of colour. Their warm, expressive orange comes in all varieties from yellow to light red, sometimes with a brownish undertone. What is particularly remarkable is the sheer size of the raw stones. Some of them are as big as a man's fist, which opens up completely new possibilities in the way they can be worked. Today, these Brazilian fire opals are setting new trends in the fascinating world of gemstones.
Hardness 7.5 / RI 1.76-1.81 / SG 3.8-4.2
Colour: Any from deep red, purple to green.
Garnet is the birthstone for January, which means that January babies have a lot of choices!
The name Garnet probably comes from pomegranate. Many ancient pieces of garnet jewellery are studded with tiny red stones that do look a lot like a cluster of pomegranate seeds! Jewellery set with garnets from Czechoslovakia was extremely popular in the nineteenth century and Bohemian garnet jewellery is still popular today, although today the garnets are mined elsewhere. When you say garnet, most people think automatically of small dark red gemstones, even though this is only one aspect of the world of garnets.
Garnet is a gemstone for all seasons. Garnets are a closely related group of gemstones that are available in every colour. Dark reds, tangerine orange, vivid lime green, soft bluish-pink, garnet is all these colours and more. There are garnets that change colour in different light, translucent green garnets that look like jade, garnets with stars, garnets that have been mined for thousands of years and garnets that were just discovered in the last decade.
Garnets have long been carried by travellers to protect against accidents far from home. In ancient Asia and the American Southwest, garnets were used as bullets because the glowing red colour was said to increase the ferocity of a wound. Garnets in legend light up the night and protect their owners from nightmares. Noah used a garnet lantern to navigate the Ark at night. The ancient world is full of praise for the carbuncle, the glowing red coal of a gemstone we now know as garnet.
Garnets are fairly hard and durable gemstones that are ideal for jewellery use, except for demantoid, which is softer and requires more protection.
Hardness 7-7.5 / RI 1.522-1.578 / SG 2.57-2.61
Colours: shade of violet-blue.
When Leif Eriksson and the other legendary Viking explorers ventured far out into the Atlantic Ocean, away from any coastline that could help them determine position, they had a secret gem weapon: Iolite. The Viking mariners used thin pieces of iolite as the world's first polarizing filter. Looking through an iolite lens, they could determine the exact position of the sun, and navigate safely to the new world and back.
The property that made iolite so valuable to the Vikings is extreme pleochroism. Iolite has different colours in different directions in the crystal. A cube cut from iolite will look a violetish blue almost like sapphire from one side, clear as water from the other, and a honey yellow from the top. This property led some people to call iolite "water sapphire" in the past, a name that is now obsolete.
Pleochroism may have been helpful in navigation but it makes things difficult for a gem cutter. If iolite is not cut from exactly the right direction, no matter the shape of the rough, its colour will not show to its best advantage.
The name iolite comes from the Greek ios, which means violet. Iolite is usually a purplish blue when cut properly, with a softness to the colour that can be quite attractive.
Iolite is readily available and surprisingly affordable. The better and richer the blue, the better. It is mined in India, Sri Lanka, Mozambique, Zimbabwe, and Brazil. The Vikings probably mined iolite from deposits in Norway and Greenland.
Iolite is relatively hard but should be protected from blows. With its attractive colour and reasonable price, it may become a jewellery staple in the future.
Hardness 6.5 / RI 1.600-1.641 / SG 2.90-3.02
Colours: Mostly dark, spinach-green but can occur in all colours.
The word yu is used in Chinese to call something precious, as in English we use gold. Jade was thought to preserve the body after death and can be found in emperors' tombs from thousands of years ago. One tomb contained an entire suit made out of jade, to assure the physical immortality of its owner. For thousands of years, jade was a symbol of love and virtue as well as a status symbol.
The Chinese knew about jadeite, travellers had brought back some jadeite from Burma as early as the thirteenth century. But China was turning inward at that time and this foreign Kingfisher Stone, as they called it, referring to the brightly coloured feathers of the bird, was not considered to be real jade. It only became popular in the eighteenth and nineteenth century when trade with Burma opened up again. The top jadeite jade is usually cut into smooth dome shapes called cabochons. Jadeite bangles are also very popular in Asian countries. Beads are also very beautiful and some important jadeite necklaces made during the art deco period have fetched hundreds of thousands of dollars in auctions in the past few years.
Because of its smooth even texture, jade has long been a preferred material for carving. The most common shape is the flat donut-shaped disc called a pi, which is commonly worn as a necklace.
While jadeite is mined today primarily in Myanmar, small quantities can be found in Guatemala. Although neolithic jadeite axes were found in Europe, it is not known where this prehistoric jadeite was mined, although it is possible that the material came from a deposit in the Alps. Nephrite is mined in Canada, Australia, the United States, and Taiwan.
jade is most often sold by the piece rather than per carat. Although the overall colour is the most important value factor, attention is also paid to translucency, texture, and also to pattern. Certain patterns, including moss in snow, are highly valued.
Both jadeite and nephrite are very durable and tough, although jadeite is slightly harder than nephrite due to its microcrystalline structure.
Hardness 6-6.5 / RI 1.518-1.526 / SG 2.56-2.59
Colours: Colourless, grey, yellow or bluish.
Moonstone almost seems magical with a ghostly shimmering glow floating in a crystalline material. The Romans thought that moonstone was formed out of moonlight. Moonstone is a variety of feldspar and the shimmer, which is called schiller or adularescence, is caused by the intergrowth of two different types of feldspar, with different refractive indexes.
In Europe, moonstone is considered the birthstone for June, although in the United States it shares that distinction with alexandrite and pearl.
Moonstones come in a variety of colours. The body colour can range from colourless to grey, brown, yellow, green, or pink. The clarity ranges from transparent to translucent. The best moonstone has a blue sheen, perfect clarity, and a colourless body colour.
Sometimes moonstone will have an eye as well as a sheen. Another related feldspar variety is known as rainbow moonstone. In this variety of labradorite feldspar, the sheen is a variety of rainbow hues.
Fine moonstone is quite rare and becoming rarer. It is mined in Sri Lanka and Southen India. The rainbow variety can also be found in Madagascar.
Moonstones are usually cut in a smooth-domed cabochon shape to maximize the effect. Sometimes they are carved to show a man-in-the-moon face. Moonstone beads also display the sheen very well and are simply stunning against a black dress.
Hardness 6.5-7 / RI 1.530-1.540 / SG 2.58-2.64
Colour: Generally black, also white & brown.
Onyx was very popular with the ancient Greeks and Romans. The name comes from the Greek word onux, which means fingernail. The story is that one day frisky Cupid cut the divine fingernails of Venus with an arrowhead while she was sleeping. He left the clippings scattered on the sand and the fates turned them into stone so that no part of the heavenly body would ever perish.
True, black isn't normally the colour one associates with fingernails. (Did Venus wear Vamp?) But in Greek times, almost all colours of chalcedony from fingernail white to dark brown and black were called onyx. Later, the Romans narrowed the term to refer to black and dark brown colours only.
Onyx which is reddish brown and white is known as sardonyx. Sardonyx was highly valued in Rome, especially for seals, because it was said to never stick to the wax. Roman General Publius Cornelius Scipio was known for wearing lots of sardonyx.
Black onyx especially shines when used a backdrop for colour play. Its fine texture also makes it ideal for carving, making it a favoured material for today's lapidary artists. In the pin by designer Susan Helmich above, a carved piece of onyx with threads of white provides a stunning backdrop for a flash of colour.
Onyx was often used as the perfect foil for carved rock crystal or the drop dead red of rubies in Art deco designs. It is also popular in marcasite jewellery. So if you would like to add a little black magic to your jewellery design, consider onyx.
Hardness 5.5-6.5 / RI 1.37-1.52 / SG 1.98-2.5
Colours: All colours , multi-coloured.
All of Nature’s splendour seems to be reflected in the manifold opulence of fine Opals: fire and lightnings, all the colours of the rainbow and the soft shine of far seas. Australia is the classical country of origin. Almost ninety-five per cent of all fine opals come from the dry and remote outback deserts.
Numerous legends and tales surround this colourful gemstone, which can be traced back in its origins to a time long before our memory, to the ancient dream time of the Australian aborigines. It is reported in their legends that the creator came down to Earth on a rainbow, in order to bring the message of peace to all the humans. And at the very spot, where his foot touched the ground, the stones became alive and started sparkling in all the colours of the rainbow. That was the birth of the Opals.
The group of fine Opals includes quite a number of wonderful gemstones, which share one characteristic: they shine and sparkle in a continually changing play of colours full of fantasy, which experts describe as “opalising”. Depending on the kind, place of occurrence, and colour of the main body, we differentiate Dark or Black Opal, White or Light Opal, Milk or Crystal Opal, Boulder Opal, Opal Matrix, Yowah Nuts from Queensland – the so-called “picture stones“, and also Mexican and Fire Opal. Opal variations are practically unlimited. They all show in their own special way that unique play of colours – except for Fire Opal, which due to its transparency, however, is nevertheless also considered a Fine Opal specimen. If Opals are lacking the typical play of colours, they are simply named “Common Opal”.
Upala, opallios or Opalus – fascination created by tiny spheres
The name Opal was probably derived from Sanskrit “upala“, meaning ”valuable stone“. This was probably the root for the Greek term “opallios”, which translates as “colour change”. In the days of Roman antiquity there existed a so-called “opalus”, or a “stone from several elements”. So the ancient Romans may already have had an inkling why the Opals show such a striking play of colours. But we will come to this later …
Pliny, the famous Roman author, called Opal a gemstone which combines the best possible characteristics of the most beautiful of gemstones: the fine sparkle of Almandine, the shining purple of Amethyst, the golden yellow of Topaz, and the deep blue of Sapphire, ”so that all colours shine and sparkle together in a beautiful combination“.
Up to the first half of the 19th century, Opals were relatively rare. But then their career boomed suddenly and made them one of the most popular gemstones, and the start of this development brought them to the gemstone cutters of the gemstone centre of Idar-Oberstein. In the era of Art Deco the Opals experienced their flourishing, with contemporary gemstone artists preferring them to all other stones because of their subdued charm, which in turn was excellently suited to be combined with enamel, another very popular material of those days.
Opal’s colour play emanates a very special attraction and fascination. But what causes this phenomenon? This question was impossible to answer for a very long time. Only when in the 1960s a team of Australian scientists analysed Opals with an electron microscope, it was discovered that small spheres from silica gel caused interference and refraction manifestations, which are responsible for the fantastic play of colours. The spheres, which are arranged in more or less compact structures, succeed in dissecting the light on its passage through the gemstone and turning it into all the colours of the rainbow, always new and always different.
Australia Classical Opal Country:
Australia is the classic Opal country and today is the worldwide most important supplier of Fine Opals. Almost 95 per cent of all Opals come from Australian mines. The remaining five per cent are mined in Mexico, and in Brazil’s north, also in the US states of Idaho and Nevada, but recently the stones have also been found in Ethiopia and in the West African country of Mali.
The history of Australian Opal began actually millions of years ago, when parts of Australia were covered by a vast inland sea, and stone sediment was deposited along its shoreline. When the water masses flooded back, they flushed water containing silica into the resulting cavities and niches in the sedimentary rocks, and also the remains of plants and animals were deposited there. Slowly the silica stone transformed into Opal, for basically Opals are simply a combination of silica and water. Or, to be more precise: Opals are a gel from silica, with varying percentages of water.
In 1849 the first Opal blocks were accidentally found on an Australian cattle station called Tarravilla . the first Opal prospectors started in 1890 at White Cliff mining the Opal rocks. And even today the eyes of Opal lovers light up when somebody mentions places like White Cliffs, Lightning Ridge, Andamooka or Coober Peddy: for these are the legendary sites of the Australian Opal fields. The most famous one is probably Lightning Ridge, the place where mainly the coveted Black Opal is found. Andamooka, where Crystal Opal and Light Opal are brought to the light of day, cam boast to be the place where the probably largest Opal was found, with a weight of 6 ,843 kilograms, the “Andamooka Desert Flame”. Coober Peddy, by the way, is a word from Aborigine language meaning „white man in a hole“. This clearly describes how Opal was in fact mined: many Opal prospectors made their home in deep holes or caves in the ground, to protect themselves from the burning heat of daytime and from the icy winds of night time. Usually they worked only with tolls such as pick and shovel. Buckets full of soil, hopefully containing Opal rocks, were pulled up out of the depths of 5 to 40 m deep shafts by hand, for this is the depth of the Opal containing crevices and cavities, which are also mined nowadays.
Being an Opal prospector is still not an easy job, although today of course there are some technical means available, such as trucks or conveyor belts. And still the hope to make the find of a lifetime which will let you live happily ever after attracts many men and women to come to the hot and dusty Australian outback.
About cabochons, doublets and triplets
In order to best bring out the play of colour in a Fine Opal, the stones are cut and polished to round or oval cabochons, or any other softly domed shape , depending on the raw material. Only the best qualities of Fire Opal, however, are suited to faceting. The Opal cutter will first of all carefully remove any impurities using a diamond cutting wheel, before working out the rough basic shape. The comes the fine cutting, the finishing with sandpaper and then the final polishing with a wet leather wheel.
Opal love to be worn on the skin
Due to the differing percentage of water, Opals may easily become brittle. They always contain water – usually between 2 and 6 per cent, but sometimes even more. Thus if stored too dry or exposed to heat over a longer period of time, Opals will show fissures and the play of colour will become paler. Therefore, Opal jewellery should be worn as often as possible, for then the gemstone will receive the needed humidity from the air and from the skin of its wearer.
From Harlequin to Peacock: Opal experts lingo
When Opal experts talk about “harlequin”, “church windows” or “needle fire”, do not be surprised. They are probably discussing Opals. The play of colour in this stone is described with many imaginative terms for various structures and phenomena, like, for example, “flame opal”, “lightning and peacock opal”, or the above named “harlequin” and “church window”.
Opals and emotions
For ages people have been believing in the healing power of Opal. It is reported to be able to solve depressions and to help its wearer find the true and real love. Opals are supposed to further enhance the positive characteristics for people born under the zodiac sign of Cancer. Black Opal is recommended to those born under Scorpio, and Boulder Opal is the lucky stone for Aries.
The fantastic colour play of Opal reflects changing emotions and moods of people. Fire and water, the sparkling images of Boulder Opal, the vivid light flashes of Black Opal or the soft shine of Milk Opal – striking contrasts characterise the colourful world of this fascinating gemstone. Maybe this is the reason why it depends on our daily mood which Opal we prefer. Opals are like human emotions: you always experience them different and anew.
Hardness 2.5-4.5/ RI 1.52-1.66 / SG 2.60-2.85
Colours: White, pink, cream, silver, green & black.
Pearls are organic gems, created when an oyster covers a foreign object with beautiful layers of nacre. Long ago, pearls were important financial assets, comparable in price to real estate, as thousands of oysters had to be searched for just one pearl. They were rare because they were created only by chance.
Today pearls are cultured by Man. Shell beads are placed inside an oyster and the oyster is returned to the water. When the pearls are later harvested, the oyster has covered the bead with layers of nacre. Most cultured pearls are produced in Japan. In the warmer waters of the South Pacific, larger oysters produce South Sea cultured pearls and Tahitian black cultured pearls, which are larger in size. Freshwater pearls are cultured in mussels, mostly in China.
The quality of pearls is judged by the orient, which is the soft iridescence caused by the refraction of light by the layers of nacre, and lustre, the reflectivity and shine of the surface. Fine pearls do not have any flaws or spots in the nacre: it has an even, smooth texture. Other factors which affect value are the regularity of the shape, size, and colour: rose tints are the most favoured.
Cultured and natural pearls can be distinguished from imitation ones by a very simple test. Take the pearl and rub it (gently!) against the edge of a tooth. Cultured and natural pearls will feel slightly rough, like fine sandpaper, because of the texture of natural nacre. Imitations will feel as smooth as glass because the surface is moulded or painted on a smooth bead.
Hardness 6.5-7 / RI 1.650-1.703 / SG 3.28-3.48
Colours: Yellowish-green, olive-green, brown-green.
Peridot is the birthstone for August.
Peridot had the power to drive away evil spirits and the power was considered to be even more intense when the stone was set in gold. Peridot was also said to strengthen the power of any medicine drunk from goblets carved from the gemstone. Small crystals of Peridot are often found in the rocks created by volcanoes and also can be found in meteors that fall to earth! A few samples of extraterrestrial Peridot have even been faceted into gems!
Peridot is the gem form of the mineral olivine. Because the iron which creates the colour is an integral part of its structure, it is found only in green, ranging from a summery light yellowish green to a 7-up bottle green.
In 1994, an exciting new deposit of Peridot was discovered in Kashmir, and these stones are among the finest ever seen. The new mine is located 15,000 feet above sea level in the Nanga Parvat region in the far west of the Himalayas Mountains in the Kashmir. Beautiful large crystals of Peridot were found, some that cut magnificent large gemstones. One stone was more than 300 carats! This new discovery, combined with fashion's passion for lime green, has revived interest in Peridot and increased the popularity of this gemstone.
Today most Peridot is mined by Native Americans in Arizona on the San Carlos Reservation. Fine large Peridot are found in Myanmar (formerly Burma) and Peridot is also mined in China and Sri Lanka.
Although Peridot is treasured in Hawaii as the goddess Pele's tears, almost all of the Peridot sold in Hawaii today is from Arizona, even though Peridot is produced by Hawaii's volcanoes. The island of Oahu even has beaches made out of olivine grains but unfortunately they are much too small to cut into Peridot!
Hardness 9 / RI 1.762-1.778 / SG 3.97-4.05
Colours: Shades of red.
Ruby has been the world's most valued gemstone for thousands of years. Ruby was said to be the most precious of the twelve stones God created when he created all things and this "lord of gems" was placed on Aaron's neck by God's command. The bible says that wisdom is "more precious than rubies," that is to say very valuable indeed. In the ancient language of Sanskrit, ruby is called ratnaraj, or "king of precious stones" and ratnanayaka, "leader of precious stones."
The most important factor in the value of a ruby is colour. The top qualities are as red as you can imagine a saturated pure spectral hue without any overtones of brown or blue. The word red is derived from the Latin for ruby, ruber, which is derived from similar words in Persian, Hebrew, and Sanskrit. The intensity of colour of a fine ruby is like a glowing coal, probably the most intensely coloured substance our ancestors ever saw. It is no wonder they ascribed magical powers to these fires that burned perpetually and never extinguished themselves. Ruby is the gem quality of the mineral corundum, one of the most durable minerals, which exists, a crystalline form of aluminium oxide. Corundum has a hardness of 9 on the Mohs scale and is extremely tough. In its common form, it is even used as an abrasive.
The most famous source of fine rubies is Burma, which is now called Myanmar. The ruby mines of Myanmar are older than history: Stone Age and Bronze Age mining tools have been found in the mining area of Mogok. Rubies from the legendary mines in Mogok often have a pure red colour, which is often described as "pigeon's-blood" although that term is more fanciful than an actual practical standard in the trade today. Myanmar also produces intense pinkish red rubies which are also vivid and extremely beautiful. Many of the rubies from Burma have a strong fluorescence when exposed to ultraviolet rays like those in sunlight, which layers on extra colour. Burma rubies have a reputation of holding their vivid colour under all lighting conditions.
Fine rubies are also found in Thailand. Thai rubies tend to be darker red in tone: a real red, tending toward burgundy rather than pink, as Burma rubies do. Some Thai rubies have black reflections, a phenomenon called extinction, which can make their colour look darker than it really is. But Thai rubies also can have a rich vivid red that rivals the Burmese in intensity. Sri Lankan rubies can also be very beautiful. Sri Lankan stones are often pinkish in hue and many are pastel in tone. Some, however, resemble the vivid pinkish red hues from Burma.
Occasionally a few fine top-quality rubies appear on the market from Afghanistan, Pakistan, or the Pamir Mountains of the Commonwealth of Independent States. The terrain in these areas has made exploration for gemstones very difficult but someday they may produce significant quantities for the world market.
Hardness 9 / RI 1.762-1.778/ SG 3.95-4.03
Colours: Shades of blue, also many other colours.
Sapphire is the birthstone for September, the month when the most babies are born. Ancient lists also name sapphire as a birthstone for April and the gemstone for the sign of Taurus. Sapphire has long symbolized truth, sincerity, and faithfulness. Tradition holds that Moses was given the ten commandments on tablets of sapphire, making it the most sacred gemstone. Because sapphires represent divine favour, they were the gemstone of choice for kings and high priests. The British Crown Jewels are full of large blue sapphires, the symbol of pure and wise rulers.
Since sapphire symbolizes sincerity and faithfulness, it is an excellent choice for an engagement ring. When Prince Charles chose a sapphire engagement ring for Princess Diana, couples all over the world were inspired to revive this venerable tradition.
The most valuable sapphires have a medium intense, vivid blue colour. The best sapphires hold the brightness of their colour under all different types of lighting. Any black, grey, or green overtones mixed in with the blue will reduce a stone's value. In general, a more pastel blue would be less preferred than a vivid blue but would be priced higher than an over dark blackish blue colour. As with all gemstones, sapphires which are "clean" and have few visible inclusions or tiny flaws are the most valuable. However some very fine sapphires, in particular those from Kashmir, have a velvety mist-like texture which enhances the richness of the blue.
Sapphires come from Sri Lanka, Thailand, Australia, and Cambodia. Nigeria, Kenya, Tanzania, China, Vietnam, Madagascar, and the United States also produce some sapphire. The most famous sources for sapphire are Kashmir and Burma, which is now known as Myanmar. Kashmir sapphire, which was discovered in 1881 when a landslide in the Himalayas uncovered beautiful blue pebbles, has a rich velvety colour prized by connoisseurs. Burma sapphires, from the same region that produces fabulous rubies, are also very fine. However, today, these two sources account only for a very small quantity of the sapphire on the market. Most fine sapphire on the market today comes from Sri Lanka, which produces a wide range of beautiful blues from delicate sky blue colours to rich saturated hues. Kanchanaburi in Thailand and Pailin in Cambodia are renowned for deep blue, even colours. Two relatively new mining localities are showing promise: Madagascar, which has produced some exceptionally fine stones in small sizes but has no organized mining yet, and Tanzania, which has long produced sapphire in other colours but is starting to produce blue colours as well from a new deposit in the south.
Sapphire is perhaps the toughest and most durable gemstone available on the market. With a hardness of 9 on the Mohs scale, sapphire is harder than any other gem but diamond and it has no cleavage plane so it cannot be cut with a single blow like a diamond. In fact, synthetic sapphire is used for scratch-resistant watch crystals, optical scanners, and other instruments because its durability can be trusted. That durability ensures that sapphire jewellery will be treasured for generations.
Hardness 6.5-7 / RI 1.691-1.700 / SG 3.35
Colours: Sapphire blue to Violet blue.
The gemstone discoveries in East Africa in the 1960s transformed the jewellery world: new varieties, new colours, and new variations on existing species made that decade the most exciting time in the gemstone industry in our lifetimes. Tanzanite is the ultimate prize of a gem safari. Its rich purples and blues often have a depth comparable to the finest sapphire. Paler Tanzanite has a delicate periwinkle colour like the eyes of Elizabeth Taylor. It is supremely rare, coming from only one place in the world, the Merelani Hills of Tanzania, in the shadow of Mount Kilimanjaro. The source of its mesmerizing colour is that Tanzanite is trichroic: that is, it shows different colours when viewed in different directions. One direction is blue, another purple, and another bronze, adding subtle depths to the colour. When Tanzanite is found in the ground, the bronze colour dominates. However, with gentle heating, the cutter can watch the blue colour bloom and deepen in the stone. Legend has it that the affect of heat was first discovered when some brown zoisite crystals laying on the ground with other rocks were caught in a fire set by lightning that swept through the grass covered Merelani hills northeast of Arusha. The Masai herders who drive cattle in the area noticed the beautiful blue colour and picked the crystals up, becoming the first Tanzanite collectors. The colour of Tanzanite is most intense in sizes above ten carats. Smaller Tanzanites are usually paler in colour. Tanzanites, which are more bluer rather than purple tend to be more expensive because the crystals tend to form with the blue colour axis oriented along the width of the crystal instead of the length. That means if the cutter chooses to maximize the purity of the blue colour, the stone cut from the rough will be smaller and will cost more per carat. The blue colour, however, is so beautiful, that the sacrifice is often worth it. Tanzanite jewellery is a little more delicate than other gemstone jewellery and should not be set in a ring that will be worn during strenuous activity. Never clean Tanzanite in an ultrasonic cleaner or resize or repair a ring set with Tanzanite because the stone could shatter in the heat of a torch. It is available in a variety of shapes and sometimes in large sizes that are perfect for an important necklace.
Hardness 6.5-7 / RI 1.63-1.64 / SG 3.35
Colours: Colourless, yellow, peach, golden, red-brown, light blue, pink, violet, light green.
GEM OF THE SETTING SUN
The Egyptians said that topaz was coloured with the golden glow of the mighty sun god Ra. This made topaz a very powerful amulet that protected the faithful against harm. The Romans associated topaz with Jupiter, who also is the god of the sun. Topaz sometimes has the amber gold of fine cognac or the blush of a peach and all the beautiful warm browns and oranges in between. Some rare and exceptional topaz are pale pink to a sherry red.
Wear topaz only if you wish to be clear-sighted: legend has it that it dispels all enchantment and helps to improve eyesight as well! The ancient Greeks believed that it had the power to increase strength and make its wearer invisible in times of emergency. Topaz was also said to change colour in the presence of poisoned food or drink. Its mystical curative powers waxed and waned with the phases of the moon: it was said to cure insomnia, asthma, and hemorrhages.
Perhaps the most famous topaz is a giant specimen set in the Portuguese Crown, the Braganza, which was fist thought to be a diamond. There is also a beautiful topaz set in the Green Vault in Dresden, one of the world's important gem collections.
Brown, yellow, orange, sherry, red and pink topaz is found in Brazil and Sri Lanka. Pink topaz is found in Pakistan and Russia.
Today we also have blue topaz, which has a pale to medium blue colour created by irradiation. Pale topaz which is enhanced to become blue is found in Brazil, Sri Lanka, Nigeria, and China.
Topaz is a very hard gemstone but it can be split with a single blow, a trait it shares with diamond. As a result it should be protected from hard knocks. Topaz is the birthstone for those born in the month of November.
Hardness 7-7.5 / RI 1.619-1.650 / SG 3.00-3.20
Colour: Virtually all colours - Colourless, pink, red, yellow, brown, green, blue, violet, black & multi-coloured.
Tourmaline's name comes from the Sinhalese word "turmali," which means "mixed." Bright rainbow collections of gemstone varieties were called "turmali" parcels. Tourmaline, occurring in more colours and combinations of colours than any other gemstone variety, lives up to its name. There is a tourmaline that looks like almost any other gemstone! Many stones in the Russian Crown jewels from the 17th Century once thought to be rubies are actually tourmalines.
Tourmaline is also of interest to scientists because it changes its electrical charge when heated. It becomes a polarized crystalline magnet and can attract light objects. This property was noticed long ago before science could explain it: in the Netherlands, tourmalines were called "aschentrekkers" because they attracted ashes and could be used to clean pipes! Tourmaline occurs in every colour of the rainbow and combinations of two or three colours. Bicolour and tricolour tourmalines, with bands of colours are very popular. Sometimes the colours are at different ends of the crystal and sometimes there is one colour in the heart of the crystal and another around the outside. One colour combination, pink centre with a green rind, is called "watermelon tourmaline" (seedless, of course!) Sometimes designers set slices of the crystal instead of faceted stones to show off this phenomenon.
Almost every colour of tourmaline can be found in Brazil, especially in Minas Gerais and Bahia. Pink and green colours are particularly popular. In 1989, miners discovered tourmaline unlike any that had ever been seen before. Pink and green tourmaline are now widely available and are especially popular in designer jewellery. Blue tourmalines are also very much in demand but the supply is more limited.
In addition to Brazil, tourmaline is also mined in Tanzania, Kenya, Madagascar, Mozambique, Namibia, Afghanistan, Pakistan, Sri Lanka, and California and Maine in the United States. Maine produces beautiful sherbet colours of tourmaline and spectacular mint greens. California is known for perfect pinks, as well as beautiful bicolour.
Tourmalines a hard and durable gemstone which can withstand years of wear. You might want to avoid steam cleaning or heat.
Hardness 5-6 / RI 1.610-1.650 / SG 2.31-2.84
Colours: Sky-blue, blue-green.
Turquoise is one of the oldest known gem materials. The Egyptians were mining turquoise in 3,200 BC in the Sinai. The blue of turquoise was thought to have powerful metaphysical properties by many ancient cultures. Montezuma's treasure, now displayed in the British Museum, includes a fantastic carved serpent covered by a mosaic of turquoise. In ancient Mexico, turquoise was reserved for the gods, it would not be worn by mere mortals.
The Apache believed that turquoise helped warriors and hunters to aim accurately. The Zuni believed that it protected them from demons. In Asia it was considered protection against the evil eye. Tibetans carved turquoise into ritual objects as well as wearing it in traditional jewellery. Ancient manuscripts from Persia, India, Afghanistan, and Arabia report that the health of a person wearing turquoise can be assessed by variations in the colour of the stone. Turquoise was also thought to promote prosperity.
In Europe even today, turquoise rings are given as forget-me-not gifts.
The most important turquoise deposits are in Iran, Tibet, China, and the Southwestern United States. Turquoise is a mineral usually found in association with copper deposits. Turquoise is sometimes mined as a by-product of copper mining.
Turquoise from Iran is often said to be the best because it is sometimes a clear sky blue with no green modifying colour and no black veins running through it. Turquoise just as fine is produced in Arizona and New Mexico. In general the bluer the blue, the more highly valued. A clear even texture without mottleing or veins is also preferred. However, some people prefer turquoise with veins, sometimes called spider webs, which set off the colour.Turquoise is porous and should be kept away from chemicals. Clean it with warm soapy water only.
Hardness 6.5-7.5 / RI 1.810-2.024 / SG 3.93-4.73
Colours: Colourless, yellow, brown, red, orange blue, violet & green.
Hindu poets tell of the Kalpa Tree, the ultimate gift to the gods, which was a glowing tree covered with gemstone fruit with leaves of zircon. Zircon has long had a supporting role to more well-known gemstones, often stepping in as an understudy when they were unavailable.
In the middle ages, zircon was said to aid sleep, bring prosperity, and promote honour and wisdom in its owner. The name probably comes from the Persian word zargun which means "gold-coloured," although zircon comes in a wide range of different colours.
Zircon occurs in a wide range of colours but for many years, the most popular was the colourless variety which looks more like diamond than any other natural stone due to its brilliance and dispersion
Today the most popular colour is blue zircon. Most blue zircon, which is considered an alternate birthstone for December, is a pastel blue, but some exceptional gems have a bright blue colour. Zircon is also available in green, dark red, yellow, brown, and orange.
Zircon is mined in Cambodia, Sri Lanka, Thailand, Myanmar, Australia, and other countries.
Zircon is one of the heaviest gemstones, which means that it will look smaller than other varieties of the same weight. Zircon jewellery should be stored carefully because although zircon is relatively hard, it can abrade and facets can chip. Dealers often wrap zircons in individual twists of paper so that they will not knock against each other in a parcel.
The wide variety of colours of zircon, its rarity, and its relatively low cost makes it a popular collector's stone. Collectors enjoy the search for all possible colours and variations.