FLUOBORITE, Bodnar Quarry, Edison, New Jersey, USA

Fluoborite fluoresces cream-white with a yellow undertone under SW UV. The blue color of the matrix is no fluorescence but rather some stray blue light that managed to pass the UV-transparent filter.

ADAMITE, Ojuela Mine, Mapimi, Mexico

Close up of small columnar crystals under short wave UV. The image is approximately 3.5 mm wide

GYPSUM, Compiègne, Paris, France

Photograph taken under long wave UV. This specimen has the shape of a "swallow's tail" that is so typical for this mineral. The activator of the orange fluorescence is unknown, possibly due to inclusions of organic material.

CALCITE and WILLEMITE, Franklin, New Jersey, USA

Photograph taken under short wave UV. The combination calcite (red)-willemite (green) is probably the most abundant as well as the most popular association from the Franklin locality. Both minerals fluoresce very strong due to the presence of a few percents of manganese.

GYPSUM, Saragossa, Spain

A 5 cm high crystal that has the shape of a bishop's hat. The matrix is covered with small gypsum crystals. Both matrix and crystal fluoresce white under long wave UV. The vertical striation of the crystal stands out very clearly due to the fluorescence. The specimen also exhibits a strong green phosphorescence.

CALCITE, Rio Grande do Sul, Brazil

The specimen consists of 1 to 2 cm long crystals of dog-tooth calcite on an earthy matrix. The fluorescence activator is probably the classic manganese and lead combination.

ZIRCON, Matongo, Burundi

Photograph taken under short wave UV. The crystal is full of cracks and fractures due to metamictisation. Zircon is practically always 'doped' with some thorium and/or other radioactive elements. The decay of these atoms generates highly energetic ionizing radiation that is capable of destroying the structure of the crystal in their vicinity. Therefore zircons are rarely found as clear, gem-quality crystals. The mineral's outer shape is preserved but the appearance becomes opaque and dull. According to 'Fluorescence: Gems and Minerals Under Ultraviolet Light', by Manuel Robbins, trivalent rare earths, particularly dysprosium, praseodymium, and europium, are suspected in this fluorescence. Since dysprosium is associated with similar yellow fluorescences, it seems to be the favorite candidate. (Thanks to Doug Mitchell)
WITHERITE, Rosiclaire, Illinois, USAThis mineral belongs to the aragonite-group and has an orthorhombic crystal structure. The hexagonal appearance is due to twinning. The central hole in the crystals suggests a pseudo-hexagonal form, rather than a hexagonal one. The photograph was made under short wave UV. The activator of the blue fluorescence is not known to me at the present time.
HALITE, Heringen, Werra, Hessen, GermanyThis beautiful specimen is composed of well-formed cubic crystals of a size up to 5 cm. The photograph was taken under short wave UV. The strong red fluorescence is most probably caused by the presence of manganese and lead, analogous to the activation mechanisms in most red fluorescing calcite. However, defects in the crystal lattice of halite are known to cause fluorescence too. Without a chemical analysis we cannot be certain about the true mechanism of this quite enthusiastic luminescence.
BARITE, Villers-en-Fagne, BelgiumBarite crystals on matrix. The largest crystal is about 5 mm long. This picture was made under long wave UV with an exposure time of about 6 minutes on Fuji film (100ASA). Fluorescence can be due to inclusions of clay or organic material.
ARAGONITE on CALCITE, Jemelle, Namur, BelgiumThe light source was short wave UV. The image width is 4 cm and the exposure time was 3 minutes. The calcite matrix fluoresces red which is probably due to the presence of small amounts of manganese (activator) and traces of lead (co-activator). The whitish green fluorescence of the aragonite needles cannot be easily explained. Most likely some trace element in the crystal structure is acting as an activator.
META-URANOCIRCITE, Les Brosses, FranceThis is a really beautiful specimen with almost perfect cubic crystals. Don't be misguided by the shape of these crystals, however. The mineral actually is monoclinic! The green fluorescence is quite common in uranium minerals. The photo was made under LW UV.
CALCITE, Santa Eulalia, MexicoIn this photo you are looking at the fractured side of a group of calcite crystals under short wave UV. Under daylight the crystals exhibit a dark brown color suggesting the presence of iron- or manganese-ions. It is well-known that the presence of iron in a crystal acts as a fluorescence-killer. However repeatedly during the growth of this group, the supply of iron seems to have been stopped. As a result, the crystals are made up of alternating layers of iron-containing and iron-free calcite. The iron containing areas of the crystals remain dark under UV-radiation whereas the iron-free areas show a strong fluorescence. Another possible explanation for this phenomenon is a zoning of the concentration of manganese in the crystals. To be effective as an activator in calcite, the concentration of manganese must be between well-defined limits. Within these limits manganese acts as an activator, outside of them it is as effective a quencher of fluorescence just as iron. If during de formation of this specimen the supply of manganese was irregular, only the areas of the crystals that have an optimal concentration of it will fluoresce.

WAVELLITE

This specimen is a real eye-catcher, with its thin layer of yellow-green Wavellite crystals shining against a dull gray background. A picture of the whole specimen would look quite flat and monotonous, however. I was ready to give up on this one when I noticed this detail on one side of the stone: the fan structure reminds me of some plant fossils, and the nice color gradient enhances the composition (other crystal groups on the stone show no color gradient). I really like the colors and the textures in this picture.Technical note: A single studio flash with standard silver reflector was placed above and lightly left of the specimen. Nikon F4S, Micro-Nikkor 60mm 2.8, Fuji Velvia.

"The Gem Hunter in Afghanistan"

This 52 minute TV documentary was filmed in August 2001. It follows The Gem Hunter, Gary Bowersox, from the Peshawar gem market over the high mountain passes of the Hindu Kush, and the steep mountain slopes to the Lapis and the Emerald mines of Afghanistan. Along the trail, The Gem Hunter meets the ghost of Marco Polo and Alexander the Great on the Silk Road. The last scene of the film is The Gem Hunter interviewing the legendary Commander Ahmed Shah Massoud, the Lion of Panjsher, twenty-one days before his assassination on September 9, 2001.
This video is an excellent companion to "The Gem Hunter"
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Pearls: very cultured

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.

The colourful world of the garnets

The specialist world was amazed a few years ago by the fantastic find of a type of garnet which had been very scarce until then. At the Kunene River, on the border between Namibia and Angola, a deposit of radiant orange to red 'spessartites' was discovered. The spessartite was originally named after the site of a find made in Germany. Spessartites had led a quiet, shadowy existence as stones for gemstone lovers and collectors until that momentous discovery in Namibia. There were hardly any used in jewellery because they were so very rare. But this new find changed the gemstone world. Since then, its wealth has increased by the addition of this unusually fine, intensely radiant orange-red gemstone. Under the trade name 'mandarine-garnet', this wonderfully orange noble garnet became world-famous in no time at all. Unfortunately, the mine in the quiet hills of Namibia was only able to be exploited for a few years. The search for gemstones in the remote bush country began to involve too much effort and became too expensive. So fears grew that this highly precious gemstone, which had shot into the firmament of the gemmological world like a rocket, might only become available in rare individual cases from the stocks of a few cutting-centres. That is, until another deposit of the orange treasures was discovered, this time in Nigeria. Their colour and brilliance are so similar to those of the mandarin garnets from Namibia that only an experienced specialist can discern the subtle differences.Now for the green garnets. Green garnets?! Is there really such a thing? Indeed there is! In fact, several green varieties are known. First there is 'grossularite', created by Nature in many fine tones of yellow, green and brown and esteemed for its many fine interim hues and earth colours. Here too, there was a spectacular find: in the final year of the 20th century, extensive grossularite deposits were discovered in Mali. These Mali garnets captivate us with their great brilliance. Even the brown, which is otherwise not terribly popular, seems vivid and natural, and goes particularly well with ethnologically inspired trends.Probably the best known green garnet is the tsavorite or tsavolite, which also belongs to the grossularite group. Tiffany's in New York gave this name to the previous emerald-green stone which was discovered in 1967 by a British geologist, Campbell R. Bridges, in the north-east of Tanzania - after the place where the discovery was made, near the Tsavo National Park with its wealth of game. The green of the tsavorite runs from vivid and light to deep and velvety and, like all garnets, it has particularly good brilliance.The star of green garnets is the rare demantoid, a gemstone for connoisseurs and gemstone lovers. Its brilliance is positively tremendous, even greater than that of the diamond. Russia's star jeweller Carl Fabergé loved the brilliant green garnet from the Urals more than anything else, and used it in his creations. Meanwhile, the demantoid is no longer quite as scarce in the gemstone trade, thanks to some new finds in Namibia. Demantoids from Namibia are of good colour and brilliance, but they lack one tiny feature: the so-called 'horse-tail inclusions'. These fine, bushy inclusions are the unmistakable, typical feature by which a Russian demantoid is recognised.

Garnet

Well yes, to a certain extent, a deep, warm red indeed being the colour most frequently found in garnets. Sadly, however, far too few people are aware that the world of the garnets is far more colourful than that. Spectacular finds, especially in Africa, have enhanced the traditional image of the garnet with a surprising number of hues - even if red does continue to be its principal colour. Thanks to their rich colour spectrum, garnets today can quite happily keep pace with changes of style and the colour trends of fashion. And thanks to the new finds, there is a reliable supply of them too. So in fact this gemstone group in particular is one which gives new impetus to the world of jewellery today.By the term 'garnet', the specialist understands a group of more than ten different gemstones of similar chemical composition. It is true to say that red is the colour most often encountered, but the garnet also exists in various shades of green, a tender to intense yellow, a fiery orange and some fine earth-coloured nuances. The only colour it cannot offer is blue. Garnets are much sought-after and much worked gemstones - the more so because today it is not only the classical gemstone colours red and green which are so highly esteemed, but also the fine hues in between. Furthermore, the world of the garnets is also rich in rarities such as star garnets and stones whose colour changes depending on whether they are seen in daylight or artificial light.And what else is there that distinguishes this gemstone group from the others? Well, first of all there is its good hardness of 7 to 7.5 on the Mohs scale. With a few minor exceptions it applies to all the members of the garnet group, and it is the reason for the excellent wearing qualities of these gemstones. Garnets are relatively insensitive and uncomplicated to work with. The only thing they really don't like is being knocked about or subjected to improper heat treatment. A further plus is their high refractive index, the cause of the garnet's great brilliance. The shape of the raw crystals is also interesting. Garnet means something like 'the grainy one', coming from the Latin 'granum', for grain. This makes reference not only to the typical roundish shape of the crystals, but also to the colour of the red garnet, which often puts one in mind of the seeds of a ripe pomegranate. In the Middle Ages, the red garnet was also called the 'carbuncle stone'. And even today, fantasy names like Arizona ruby, Arizona spinel, Montana ruby or New Mexico ruby are still rife in the trade.The warm red of the garnet illuminated Noah's ArkGarnets have been known to Man for thousands of years. Noah, it is said, used a garnet lantern to help him steer his ark through the dark night. Garnets are also found in jewellery from early Egyptian, Greek and Roman times. Many an early explorer and traveller liked to carry a garnet with him, for the garnet was popular as a talisman and protective stone, as it was believed to light up the night and protect its bearer from evil and disaster. Today, science has taught us that the garnet's proverbial luminosity comes from its high refractive index. Not only do garnets have many colours; they also have many names: almandine, andradite, demantoid, grossularite, hessonite, pyrope, rhodolite, tsavorite, spessartine, and uvarovite, to quote but a few. But let us restrict ourselves to the most important and begin with the red garnets. First, there is the fiery red pyrope. Its spirited red, often with a slight brownish nuance, was a gemstone colour much in demand in the 18th and 19th centuries. Garnets from a find in the north-eastern part of the former kingdom of Bohemia - small stones of a wonderful hue - were world-famous at that time. In Europe, they were worked into jewellery a good deal, especially in the Victorian period. That genuine Bohemian garnet jewellery was traditionally set with a large number of small stones, which were close to one another like the seeds of a pomegranate, with their red sparkle. And today too, garnets are still found in former Czechoslovakia and set close together according to the old tradition, the attractiveness of classical garnet jewellery thus consisting mainly in the beauty of the gemstones. The larger central stones of the typical 'rosettes' are also mostly of garnet, though they belong to a different category. For the 'almandines', named after Alabanda, an ancient city, have a chemical composition that differs somewhat from that of the pyrope. And why, one might ask, are they used as central stones? That's quite simple: because Nature has created the pyrope almost exclusively in small sizes, whilst allowing the almandine to grow in rather larger crystals. A further garnet variety, also red, is the rhodolite. a mixed crystal of almandine and pyrope. This popular garnet is of a magnificent velvety red with a fine violet or raspberry-red undertone. Originally found in the USA, it now comes mainly from the gemstone mines in East Africa, India and Sri Lanka

Prehnite from South Africa:

Prehnite, a form of calcium aluminum silicate, has a vitreous mother-of-pearl luster. It occurs in a range of green hues, from yellow-green to apple-green. It is typically translucent, so you'll usually find it cut as cabochons. We've jus received a new stock, with some impressive pieces up to 50 carats.

Color-Change Sapphire from Tanzania:

Some rare sapphire changes color form violet to blue, depending on the lighting conditions. We've found some excellent color-change sapphire from Tanzania, many of them completely untreated. Most pieces are in the 1 to 1.5 carat size, but we have one remarkable 4.6 carat piece that is a real collector's item.

Tsavorite Garnet from Tanzania:

We have just purchased some very fine pieces of rare tsavorite garnet, including a number of matching pairs in round and trillion shapes. These are mostly clean pieces with very good color and outstanding brilliance.

Unheated Sapphire from Tanzania, Madagascar and Thailand:

It is increasingly hard to find completely untreated sapphire, but we have just added several dozen new pieces to our collection. For the discriminating gem buyer who will accept nothing less than 100% natural, you'll find pink, blue, green and violet pieces, all guaranteed to be unheated. We've just added some new matching pairs as well.

Ruby Cabochons from Madagascar:

Recently we've found some excellent ruby cabochons from Madagascar. These are pure red and some are clean enough to be graded transparent. These cabs make wonderful jewelry and the price is extremely attractive. You'll find sizes all the way from 2 carats up to 35 carats

Chrysocolla from Mexico

Chrysocolla is a hydrous copper silicate with that is found in several places in the world, including Russia, Nevada in the USA, the Congo, Chile, Israel and Mexico. Often confused with turquoise, chrysocolla is often found in unusual multicolor combinations as well as in blue or green. We've purchased some interesting pieces from Mexico, in a variety of fascinating patterns.

Rutile Quartz from India

Rutile (or rutilated) quartz is clear or smoky quartz with inclusions of rutile crystals. Rutile is the mineral name for natural crystals of titanium dioxide. While most varieties of transparent quartz are valued most when they show no inclusions, rutilated quartz is valued specifically for the lovely patterns formed by the delicate golden needles of rutile inside it. We've just purchased an interesting lot from India of this fascinating gemstone. Each piece is entirely unique.

New and Interesting Gems -- updated January 21st

20.83 ct VVS-VS Blue Sapphire from Madagascar: From time to time we acquire a truly rare gemstone. This 20.83 ct blue sapphire from the Diego Suarez mine in Madagascar certainly qualifies. Gem-quality sapphires of this color and clarity are extremely rare in this extraordinary size. This stunning gemstone has remarkable brilliance and luster. Click on the photo to see the detail page and view the video of this exceptional gem.