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Actinolite: Actinoliet, Actinolita, Actinote, Aktinoliitti, Aktinolita, Aktinolit, Aktinolith, Aktinolīts, Aktynolit, Актинолит, 緑閃石, אקטינוליט, 阳起石
Ca2(Mg,Fe+2)5Si8O22(OH)2
Actinolite synonym, variety of Amphibole.
Etymology : from the Greek "aktis" = ray and "lithos" = stone.
Discovered in 1794 by Kirwan.
Crystal System : Monoclinic
Density : 3.0 to 3.2
Hardness : 5/6
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Afghanite: (Na,Ca,K)8 (Si,Al)12 O24 (SO4,Cl,CO3)3 H2 OAfghanite -  ©gemfrance.com
Mineral species discovered in 1968. Etymologie : Name of the country (Afghanistan). Standard locality : Lapis Lazuli mine of Sar-E-Sang, Badakshan.
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Agate: Achat, Achát, Agaat, Agat, Agata, Ágata, Agatas, Agate, Ahat, Ahāts, Ahhaat, Akaatti, Akik, Агат, 瑪瑙, メノウ, אגט, العقيق, โมรา.
SiO2
Etymology : from "Achates", a river in Sicily.

Agate- "cross agate":Agate croix -  ©gemfrance.com
This variety contains iron oxide. Depending on the angle at which the cabochons are cut, it is possible to highlight geometric forms, including crosses.
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Agate- "landscape agate":img368|right>
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Aquamarine: Acquamarina, Acvamarin, Aguamarina, Água-marinha, Aigue-marine, Akuamarin, Akvamariin, Akvamariini, Akvamarin, Akvamarīn, Akvamarīns, Akvamarinas, Akwamaryn, Aquamarijn, Aquamarin, Ngoc berin, 海藍寶, Аквамарин, אקוומרין, アクアマリン
(Be3 Al2 Si6 O18).
It is the blue variety of the Beryl group. It’s color is due to iron. The most sought after gems have an intense blue color. The largest known aquamarine was 48.5cm long with a diameter of 41cm and weighed 110.50 kg.
For more information, follow this link on ICA website->
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Alexandrite: Alejandrita, Aleksandriidina, Aleksandriitti, Aleksandritas, Aleksandryt, Alessandrite, Alexandriet, Alexandrit, Alexandrita, Александрит, アレキサンドライト, 亞歷山大石, 金緑石 Alexandrite  -  ©gemfrance.com
Etymology : this gem was named in honor of the Russian Tsar Alexander II. According to the legend, this gem was first discovered in the Ural Mountains on the day he was born.
Alexandrite is an extremely rare gemstone. It’s a variety of chrysoberyl.
Alexandrite’s originality is its color change depending on the wavelength of the light source it is viewed under. Under sunlight or a fluorescent lamp, the stone will be green. Under incandescent lighting, the stone will be violet to red. It is said "Emerald by day, Ruby by night".
Alexandrite owes its color to the presence of Chromium.
Synthetic sapphire with an "alexandrite effect" has been created. This is sold as natural alexandrite and often at high prices.

A warning to touristes ! There is no natural Alexandrite mine in Alexandria, Egypt, despite what you will hear in the souks and a fair number of jewellery stores in Egypt...
Natural Alexandrite is one of the rarest gemstones. It’s price is therefore very high.

Allanite(Ce,Ca,Y)2 (Al,Fe+2,Fe+3)3 (SiO4)3 (OH)Allanite   ©gemfrance.com
Etymology : From Thomas ALLAN Scottish mineralogist who discovered this mineral (1777-1833).
Locality : 1810 by Thomson, in IGLORSOIT, Gröenland.
Allanite is from the epidote group.

Amazonite: KAISi3O8Amazonite ©gemfrance.com
Etymology : from the name of the Amazonia river, from the first dicovery.
Gem from the feldspar family. Amazonite is a Microline.
Its blue-green color is coming from lead.

Amber: Agstein, Aidstein, Allingit, Allingita, Allingite, Ambar, Ámbar, Âmbar, Ambra, Ambre, Ambroit, Ambroita, Ambre, Ambroid, Ambroite, Barnsteen, Bärnsten, Bernstein, Borostyán, Bursztyn, Chihlimbar, Chryselectrum, Dzintars, Gintaras, Glessum, Glesum, Jantar, Kehribar, Lyncurium, Lynx-stone, Merevaik, Meripihka, Raf, Rav, Succinit, Succinita, Succinite, Hổ phách, 琥珀, コハク, Янтарь, كهرمان, ענבר, 호박, อำพัน
C12 H20 O
Etymology : from the Arabic « al ambar ».
Amorphous fossilized resin. Can contain insects that were trapped in the resin. Beware of imitations!

Baltic amber is a resin which came from a now extinct tree 30 - 40 million years ago : the Pinus Succinifera (succinum is the ancient latin name for amber, electrum was the Greek name), this tree grew in an area now under the Baltic Sea.

Buried under layers of mud and sand, it is now found when storms rip it from the seabed. Because of its low specific gravity, the amber released from its prison rises to the surface and washes up on the beach where, for centuries, the local inhabitants have collected it for sale.

Towards the end of the 1600’s, large deposits of amber were discovered in the Baltic inland ; today these deposits are still exploited and furnish a large part of the amber found on the market.

Amber is very soft, (with a hardness of around 2,5) and therefore easy to work. Because of this, it was used for small sculptures and precious gems as far back as prehistoric times.

From time immemorial, amber has been attributed with "magic" and therapeutic properties, particularly because of some of it’s mysterious qualities such as the ability to attract hair and wool fibers after it has been rubbed. The principal of static electricity were not yet known.
The unexplainable presence of plant fragments and tiny insects intrigued and mystified.

Many of it’s mysteries have since been explained. However, even today Amber is still the subject of superstitions : some people still attribute it with certain therapeutic powers. It is used in the treatment of impotence (it is said that one has only to keep it in one’s pocket !!!), in nervous system and digestive tract disorders and in some beauty creams.

Its use in the manufacture of cigarette holders and pipes derives from an ancient Arab belief that amber prevents the transmission of contagious diseases which could be spread by the shared use of a narghile.(water pipe)

In Baltic countries, it is traditional to put an amber necklace around the neck of a baby in order to keep away disease.

Following the film "Jurassic Park", amber once again became fashionable and attracted renewed scientific interest, particularly because of the inclusions which allow scientists to further their knowledge of evolution and the development of living organisms.

Ambre à insecte  -  ©gemfrance.com





For more information, see the links below:

-  Ambre balte par Gianfranco Rocchini:

-  American Museum of Natural History

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Amethyst: Amatista, Amethist, Améthyste, Ametista, Ametistas, Ametisti, Ametists, Ametiszt, Ametüst, Ametyst, Аметист, 紫水晶, アメシスト, เขี้ยวหนุมาน, Αμέθυστος, אחלמה, ამეთვისტო
SiO2
Etymology : the word originates from the latin "amethystos", with a possible Greek origin, the negative prefix « a » associated methustes « drunk », because water poured into a violet coloured glass appears to be wine, which when consumed obviously does not cause drunkness.
Because of this, amethyst was considered as a talisman that protected against drunkeness.

The color of amethyst remains stable up to 250 °C ; above that, the majority of amethysts lose its color. Around 500 °C, amethyst turns lemon yellow, but again loses its color if the temperature reaches 600 °C, following which the quartz becomes milky due to the formation of infra-microscopic water.
The vast majority of citrine on the gemstone market is actually amethyst that has undergone heat treatment.
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Ametrine: Ametrin, Ametrinas, Amétrine, Ametrino, Ametrīns, Ametryn, 紫黃晶, 双色水晶 (又名紫黄晶), อเมทริน.
SiO2Ametrine -  ©gemfrance.com
Together amethyst (purple) and citrine (yellow) that is only found in eastern Bolivia, in the center of the tropical forest of Chaco, situated 30 km from Brazil, in the province of Santa Cruz, in one mine : Anahi. From Puertu Suarez in Amazonia, it takes one day and one night boat trip to get to the Ametrine mine.
Because of its rarity, the Bolivians proudly name it "Bolivianite".

Legend has it that on her deathbed, Princess Anai offered this fascinating gemstone to her husband as proof of her eternal love.

Mining was clandestine and anarchaic during the 70’s through the 90’s. Since then, the new owner has reorganized the mining operations. Now, the miners work for 35 consecutive days, cut off from the rest of the world, and then have 15 days off. They are paid based on the weight of ametrine that is extracted. But once cut, only 1% of the gem rough will yield high quality ametrine stones.
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Andalusite: Al2SiO5 Andalousite - ©gemfrance.com
Etymologie : From "Andalusia", the Spanish province.
Discovered by Delametherie in 1789.
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Ammolite: Ammolite ©gemfrance.com
In 1908 a member of the National Geological Survey team found mineralized fossils of ammonite along the St. Mary’s River in Alberta. It was not until 1981 that enough high quality Ammolite was discovered to make mining commercially viable. Extremely rare and beautiful, Ammolite’s iridescent colors glow with all the colors of the rainbow. Years of tectonic pressure coupled with temperature and the precise mineral composition of the soil, created this beautiful gem from the fossilized remains of the ammonite shell. All gem-grade Ammolite comes from a single mine in North America-there is only one source ! Ammolite was granted official gemstone status in 1981 by CIBJO International Commission of Colored Gemstones-making it the most recent stone to be classified as a precious Gem.
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Andesine: アンデシン (Na,Ca) (Si,Al)4 O8

This new gem is known to mineralogists but very rare in gem quality. We present on this site the new discovery made in the Democratic Republic of Congo in 2002. Andesine belongs to the group of plagioclase feldspar. The red color of this Andesine is due to the presence of copper.

Since its discovery in the area of Goma, no other Andesine coming from the DRC has been available on the market.

Andesine is an intermediate member of the plagioclase series, close to Labradorite. The name depends on the ratio of Sodium and Calcium between Albite (Na(AlSi3O8) and Anorthite (Ca(Al2Si3O8). The stones examined by different laboratories have shown less than 50% of Calcium, thereby entitling them to be called Andesine (AGTA-USA / Nantes University - France / CCIP - France / JGGL - Japan / AIGS - Thailand).

Our 57 largest stones underwent chemical analysis by the AIGS. All of these stones were confirmed to be Andesine.

The red color of these Andesines is due to copper. Their clarity is exceptional. Red feldspar gemstones are extremely rare. The most well known is the Labradorite from Oregon, also called “Oregon Sunstone”, but these are never found in sizes as large or in colors as red as this new discovery. The Congo Andesine contains more copper than the Oregon Sunstone.

Only a few hundred flawless "top red" stones were cut, and we have almost all of the world stock of this Congo Andesine. There has been no further Andesine from this source offered on the market since we purchased these stones. We have also other Andesine that has an orange-red or orange color in a lower price range. You may find other Andesine on the market with an orange color and/or visible inclusions in an even lower price range, however we do not carry stones in this lesser quality.

A few rare specimens from the same source are yellow or green, and a few have an “alexandrite effect” color change (green / red, yellow/red). Contact Us.

Since 2002, another discovery in China has produced Andesine of lesser quality than those from the Congo. According to our sources, this pocket of Andesine has also been depleted.

Another new source was recently discovered in Tibet in 2005.
The "Chinese Andesine" (also called "Tibet Sunstone" or "Tibet Andesine") on the market is not as pure, and the red stones appear to have a brownish tone that is not present in the Andesine from our inventory. We also noted that the "Chinese Andesine" has a "sleepy" appearance compared to the stones found in the Congo.

After the 2006 Tucson gemshow (USA), we can confirm that the availability of high quality stones will remain weak. Even if another deposit of Andesine should be discovered, this gem will still remain much rarer than a diamond !

These news are excellent for the popularity of Andesine. More production will make it possible for this gem to become better known and therefore, more sought after. As with all gems, the factors of demand vs. supply ensure that the Congo Andesine can only gain in value.

Like Tanzanite, Andesine has a hardness of 6.5 (Mohs scale), and is therefore suitable for jewelry. Unlike Tanzanite, these stones are not heated or enhanced in any way, the bright beautiful red color is as it came from the earth, and not induced by heat treatment, as is almost always the case with Tanzanite. In addition, Andesine is considerably rarer than Tanzanite ; compare the few hundred stones of Andesine found to date to the ten of thousands of Tanzanites. Yet, our price per carat for top quality Andesine is about the same price as top quality Tanzanite.

Hardness: 6.5. Refractive index: 1.551 / 1.560. Specific gravity: 2.67. Birefringence: 0.009.
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Andradite:
See Garnet - andradite->

Anglesite: アングレサイト Pb SO4Anglésite   ©gemfrance.com
Discovered by Beudant in 1832.
Etymology : from the locality of origi n: Parys Mine, Anglesey Island, Wales.
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Apatite: 燐灰石 img375|right>
Etymology : from the Greek "apatan" = to mislead.
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Astrophyllite:Astrophyllite   ©gemfrance.com
Etymology : from the Greek "astron" = star et "phullon" = leaf, because of it’s appearance.
Discovered in 1854 by Sheerer.
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Axinite: アクシナイトAxinite   ©gemfrance.com
Etymologie : from the Greek "axine" = axe, because of the crystal form resembles a "francisque", a two-headed axe.
Location of origin : St Christophe - Bourg d’Oisans - Isère - France.
Axinite is not the name of a mineral species but of a group forming a series from ferro-axinite through manganaxinite.
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Azurite: Cu3 +2 (CO3)2 (OH)2Azurite   ©gemfrance.com
Discovered by Beudant in 1824.
Etymology : from Persan "LAZAWARD" = blue, regarding its color.

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