Chrome Tourmaline Buying Guide


chrome tourmaline buying - fancy oval
“Chrome Tourmaline,” fancy brilliant oval cut, 2.12 cts, Tanzania. © Dan Stair Custom Gemstones. Used with permission.

Rare chrome tourmaline can show an emerald-like green color. With a highly desired color and tourmaline’s excellent jewelry stone qualities, this gem ranks as one of the top commercial stones on the market today. I hope my personal opinions and experiences dealing with this gem can help your chrome tourmaline buying go smoothly.

What Makes a Green Tourmaline a Chrome Tourmaline?

Basically, the green tourmaline or verdelite category includes any shade of green. However, chrome tourmalines differ chemically from their green cousins. The presence of chromium produces its emerald-like color. For this reason, chrome tourmalines are usually distinguished from other green varieties of tourmaline. (Vanadium can also produce green color in tourmalines and has been found in stones identified as chrome tourmalines).

Many consider chrome tourmaline’s deep green the top green color for tourmalines. Thus, you’ll find a significant price difference between these tourmaline varieties. Chrome tourmaline’s price per carat is significantly higher and can jump considerably after one carat. Green tourmaline’s price per carat doesn’t jump much before reaching five carats.

See our green tourmaline buying guide for additional information on non-chrome green tourmalines.

Chrome Tourmaline Buying and the 4 Cs

With a hardness of 7 to 7.5 and no cleavage, tourmalines of all types have good durability. However, watch out for stones with flaws/low clarity. These may be weaker.

Color

Some people prefer their chrome tourmalines a little on the dark side because of their deep, intense green flash. However, I recommend an emerald green with a medium saturation. I try to look for a pure green color, but this is hard to find. In many stones, you’ll find blue/black or yellow tones. I would give these a lower grade.

Chrome tourmaline tends to be very intense in saturation. When gem shopping, make sure a stone has good quality color and fire under normal light conditions. Gem show and dealer lighting can be very intense. Usually, this will make a stone look much brighter than it really is.

Clarity

Generally, tourmalines are Type II clarity stones, showing inclusions. However, you can commonly find eye clean green tourmalines, including chromes. While you can find lower quality material more easily, I recommend only buying chrome tourmalines graded IF (internally flawless) to VS (very small inclusions).

chrome tourmaline buying - 0.45 cts
“Bright Green Chrome Tourmaline,” 0.45 cts, Africa. The inclusions visible in the photo don’t affect this stone. © All That Glitters. Used with permission.

Cut

Due to their intense saturation, most chrome tourmalines will be too dark if not cut properly or in the correct size. (Too often, they’ll be cut too large for the saturation of the rough). For more saturated and larger stones, I’d recommend brilliant or checkerboard cuts. However, if your rough isn’t too dark, you can have just about any kind of cut you’d like.

You can find cut chrome tourmalines in many styles. Cutting affects the value of the finished stone significantly. If you’re buying a cut stone, ask yourself: is it cut to high custom standards? Or, is the stone cut to average commercial quality?

Please note, you’ll encounter different levels of commercial cutting. While nowhere near top custom-cut quality, some commercial cutting beats out low-quality commercial cutting. Signs of quality commercial cutting include:

Carat

You’ll find chrome tourmalines most frequently available for purchase in smaller size ranges, up to 2 carats. Stones from 3 to 8 carats are available but harder to find. Locating a stone over 8 carats will be a challenge, especial something light enough in color to look good cut.

chrome tourmaline buying - commercial cut

Spotting Gemstone Treatments When Chrome Tourmaline Buying

Although tourmalines in general commonly receive heating and radiation treatments, chrome tourmalines may not. Heating may lighten green colors but often doesn’t produce good results. Radiation can produce spectacular color changes but won’t help chromes. (Editor’s Note: consumers should assume all tourmalines are heated).

Synthetic tourmaline isn’t commercially available. However, simulants (imitations) do appear for sale occasionally. Quartz, natural or synthetic, can be stained or dyed green to resemble chrome tourmaline. You may also encounter synthetic spinels misrepresented as chrome tourmalines.

Unscrupulous vendors may try to pass green tourmalines as chrome tourmalines. A Chatham or Chelsea filter examination can help confirm the presence of chromium. Red or pink may indicate chromium. (Editor’s Note: a spectroscopic examination can also determine this).

To protect yourself from undisclosed gem treatments and substitutions, do business with experienced, reputable gem dealers who cut their own stones.

Other Considerations For Chrome Tourmaline Buying

The African country of Tanzania is the only known producer of chrome tourmalines.

I think high-quality chrome tourmalines will continue to increase in value. Of course, I offer no guarantees. However, just about any quality stone can appreciate.

chrome tourmaline buying - dravite
“Dravite,” green chrome dravite tourmaline, Merelani Hills (Mererani), Lelatema Mts, Arusha Region, Tanzania. © Rob Lavinsky, www.iRocks.com. Used with permission.
Gram Faceting Archive of Information
This edited version of an article by the late Jeff Graham is part of a special archived informational series from Gram Faceting. Used with permission.