Intense green color…only found in East Africa
Chrome Tourmaline is a vivid green tourmaline found in the rich gem deposits of East Africa.
This dravite Tourmaline is colored by the trace elements vanadium and chromium. The gems actually turn pink to pinkish-red under the Chelsea filter!
The finest gems rival the colors of top quality Tsavorite, and they are frequently used in place of them.
Chrome Tourmaline is rare in sizes above 3cts and usually saturates in color as the stones get larger.
Some Chrome Tourmalines have a special kind of color change phenomenon known as the Usambara Effect.
In florescent light these gems show a green or dark green color, and in incandescent light they turn to a red, orangey-red or brownish-red color. Under incandescent light, many times thinner parts of the gem will appear green and thicker parts will appear red.
The effect is dependent on the path length of light through the gem and modified by the type of illumination and varying pleochroic directions of the crystal.
The Usambara Effect is named after the beautiful Usambara Mountains which lie at the southern end of the Umba Valley, Tanzania. The phenomenon was first observed with Chrome Tourmalines found in this area, but has since been seen with Chrome Tourmalines from other areas as well as in other gems too.
The tourmaline family is found in many different locations around the world including Brazil, Nigeria, Mozambique, USA (California, Maine), Congo, Tanzania, and has one of the widest color ranges found in gemstones.
Since tourmaline grows in long crystals referred to as “pencils” they are frequently cut as elongated emerald cuts that are perfect for pendants, earrings and even some rings.
Tourmaline is one of the birthstones for October and celebrates the 8th Anniversary.
Lots of choice in colors for October birthdays!
We have many more shapes and sizes available in Chrome Tourmaline – please contact us if you don’t find what you are looking for in our online inventory.
deep forest green
RI = 1.624 (+/-0.005) – 1.644 (+/-0.006) DR
SG = 3.06 (-0.05, +0.15)
Dispersion = 0.017
Hardness = 7-7.5
suitable for use in jewelry
Pyroelectric – becomes electrically charged when heated
see policy on Treatment Disclosure
Distinctively colored by chromium and vanadium to give a beautiful range of
Calibrated sizes up to 6mm
All standard cuts
Tanzania (Landanai, Morogoro, Umba Valley) and Kenya (Taita-Taveta)