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 Home / Gem Library / Natural Gemstones / Chrome Tourmaline November 24, 2017  


Natural Chrome Tourmaline
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There are 238 Chrome Tourmaline(s) available at Multicolour.com


Chrome Tourmaline from East Africa is a very attractive shade of green which derives it's unique coloration from the presence of chromium or vanadium.


Known Facts
Color Key: dark green, light green, yellowish green
Refractive Index: 1.624(+.005, -.005) - 1.644(+.006, -.006)
Chemical Composition: (NaCa)(LI,MgFe,Al)9B3Si6(O,OH)31
Hardness: 7-7.5
Density: 3.06 (.05, +.15)
Crystal Group: Hexagonal
Ocurrence: East Africa

Tourmaline is a gemstone noted for the large number of colors in which it occurs. Since chrome tourmaline is much more rare and valuable than ordinary green tourmaline, chemical analysis has become an increasingly important part of accessing tourmaline value. In the field, the chrome deposits normally produce similar material so if one stone tests as chrome, we can assume that all the tourmaline from that deposit should also be chrome bearing.

The easiest way to determine the presence of chromium or vanadium is by use of the Chelsea or Chrome filter. The dark colored filter will appear red upon inspection of a transparent illuminated chrome or vanadium bearing material.

A desktop spectrascope may not readily reveal any chromium content because the chrome tourmaline spectrum is a combination of chrome and vanadium and we do not see the distinct chromium lines like we see in ruby, emerald, and alexandrite.

For a more detailed analysis of gemstone chemistry (chrome or vanadium content), well equipped labs use, EDXRF; (Energy dispersive X-ray fluorescence).


Illustrations
Chrome Tourmaline Chrome Tourmaline
Check our Top, Largest, Smallest or Latest Chrome Tourmaline's.


Chrome Tourmaline Stats/
Popularity Index: 41797084hits
Total Items: 238items
Total Weight: CTS 904.35
Cheapest: USD 0.59
Most Expensive: USD 4735.80
Largest: CTS 20.06
Smallest: CTS 0.00
Last Added: 11/24/17 05:23:58

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