Friday, January 4, 2008
Aquamarine - as a mineral
| Aquamarine | |
|---|---|
 Aquamarine | |
| General | |
| Category | beryl variety |
| Chemical formula | Be3Al2Si6O18[1] |
| Identification | |
| Color | transparent (or can be translucent if included), greenish blue to blue green, typically light in tone[1] |
| Crystal system | hexagonal[1] |
| Cleavage | very difficult in one direction, almost never seen[1] |
| Fracture | conchoidal[1] |
| Mohs Scale hardness | 7.5 - 8[1] |
| Luster | vitreous to resinous[1] |
| Polish luster | vitreous [1] |
| Refractive index | 1.577 - 1.583 (+/- .017)[1] |
| Optical Properties | Double refractive, uniaxial negative[1] |
| Birefringence | .005 - .009[1] |
| Dispersion | .014[1] |
| Pleochroism | weak to moderate, blue and greenish blue; or different tones of blue with lighter tones associated with the optic axis direction [1] |
| Ultraviolet fluorescence | inert[1] |
| Absorption spectra | indistinct lines at 537 and 456nm. Depending on the depth of color, there is a strong line at 427nm.[1] |
| Specific gravity | 2.72 (+.18, -.05)[1] |
Composition
Aquamarine is a beryl with a hexagonal crystal structure and a chemical formula of Be3Al2Si6O18, a beryllium aluminium silicate mineral. It has a specific gravity of 2.68 to 2.74 and a Mohs hardness of from 7.5 to 8. Aquamarine typically is on the low end of the specific gravity range, normally at less than 2.7. The pink variety exhibits a high specific gravity of around 2.8. Refractive indices range around 1.57 to 1.58.
Locations of deposits
It occurs at most localities which yield ordinary beryl, some of the finest coming from Russia. The gem-gravel placer deposits of Sri Lanka contain aquamarine. Clear yellow beryl, such as occurs in Brazil, is sometimes called aquamarine chrysolite. When corundum presents the bluish tint of typical aquamarine, it is often termed Oriental aquamarine.
In the United States, aquamarines can be found at the summit of Mt. Antero in the Sawatch Range in central Colorado. In Brazil, there are mines in the states of Minas Gerais, Espírito Santo and Bahia. Zambia also produces nice aquamarine as well as Madagascar, Malawi, Tanzania and Kenya. Much of today's aquamarine is heated to give it a better color blue. The deeper the blue color, the more valuable the gem is considered.
The biggest aquamarine ever mined was found at the city of Marambaia, Minas Gerais, Brazil, in 1910. It weighed over 110 kg, and its dimensions were 48.5 cm long and 42 cm in diameter.
Aquamarine is the official state gem of Colorado.
Culture and historical/mythical usage
- Aquamarine (along with Bloodstone) is the birthstone associated with March. It is also the gemstone for the 19th Anniversary.
- People in the Middle Ages thought that aquamarine could magically overcome the effects of poison.
- Ancient sailors traveled with aquamarine crystals, believing that it would ensure a safe passage, and guarantee a safe return; they often slept with the stones under their pillow to ensure sound sleep. They believed the siren’s (mermaid) fish-like lower body was made of aquamarine.
source : http://en.wikipedia.org/wiki/Aquamarine
Monday, December 24, 2007
Link to a forum : Pink Diamond Ring
26/11/2007 (11 posts)
First comment from this forum :
"I have wanted a pink for a long time now and my anniversary is coming up, my husband always gets me what I want. So my question is where should I get my pink? Anybody have any suggestions? I want a nice stone and it must be certified, I live in California, but I will consider online purchases too. Thanks guys.
Annie"
see this forum at : http://www.jewelryforum.net/forum/showthread.php?t=575
Tuesday, December 11, 2007
Link to a forum : Syntethic Gemstones?
First comment from this forum :
Aug 2004 (16 posts)
"How can I tell if gemstone jewelry I buy online is not man made or syntethic?"
Link to a forum : Diamond Necklace
First comment from this forum :
Sep 2005 (10 posts)
"This diamond necklace is selling for half of it's appraised value. I love it, I would love to wear it to my wedding, but someone told me diamonds are for ladies who have been married for 6 years. Is this true?"
Thursday, December 6, 2007
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