Green Tourmaline (Verdelite) Buying Guide


verdelite - pear cut
“7.64-ct Pear Shaped Tourmaline,” green with blue overtones, Aricanga Mine, Minas Gerais, Brazil. © All That Glitters. Used with permission.

You’ll frequently find green-colored tourmaline or verdelite on the market. Green is a popular color, and tourmalines make excellent jewelry stones. To help your verdelite shopping go smoothly, I’ll share my personal opinions and experiences dealing with this gemstone.

What’s the Difference Between Green Tourmaline and Chrome Tourmaline?

Green tourmaline encompasses any shade of green. Many consider chrome tourmaline’s deep green the top green color for tourmalines. However, chrome tourmaline differs chemically. Chromium produces its emerald-like color. For this reason, chrome tourmalines are usually distinguished from verdelites.

You’ll also find a significant price difference between these tourmaline varieties. Chrome tourmaline’s price per carat is significantly higher and can jump considerably after a carat. Verdelite’s price per carat doesn’t jump much before reaching five carats.

If you like green and you’re on a budget, green is the tourmaline for you.

I’ll deal with chrome tourmalines in another article. The following information refers just to green tourmalines.

verdelite and chrome tourmaline colors
Left, a chrome tourmaline (Africa, 10.05 cts). Right, two green tourmalines or verdelites (Brazil, 9.68 and 14.75 cts). Photo © Joel E. Arem, PhD, FGA. Used with permission. (Cropped to show detail).

Verdelite Buying and The Four 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

Green tourmaline’s color ranges from yellow-green to green to blue-green. As long as green predominates, you have a verdelite. If a tourmaline shows more blue than green, you have an indicolite or blue tourmaline. This is a judgment call. However, be advised that some vendors may prefer to sell a blue-green stone as indicolite because blue brings more money.

Many people like mint green, thus making it one of the most valuable shades. Generally, lighter and brighter stones sell higher.

verdelite - Brazil
“Colored Stones,” green tourmalines, 5 mm each, Brazil, by Mauro Cateb. Licensed under CC By 2.0. (Cropped to show detail).

Clarity

High clarity verdelite stones, IF (internally flawless) to VVS (very, very small inclusions), are available. Look to quality-cut gem dealers. Of course, you can find lower quality material more easily. However, green tourmaline are usually fairly clean. I recommend only buying green tourmalines graded IF to VS (very small inclusions).

Cut

If your rough isn’t too dark, you can have just about any kind of cut you’d like. For more saturated and larger stones, I’d recommend brilliant or checkerboard cuts.

You can find cut green 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 can purchase green tourmalines in just about any size. You can easily find stones ranging from 1 to 6 carats. Less plentiful but still available are 8 to 15-carat stones. For stones over 15 carats, you’ll need to explore upper-end or collector’s markets.

Spotting Gemstone Treatments When Buying Verdelite

Although tourmalines in general commonly receive heating and radiation treatments, green 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 green tourmalines. (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 verdelite. You may also encounter synthetic spinel misrepresented as green tourmaline. (On the flip side, unscrupulous vendors may try to pass verdelites as chrome tourmalines).

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

Other Considerations for Verdelite Buying

Origin

A verdelite’s origin normally doesn’t factor into value. Of course, gem collectors may want to know this. It’s always nice to know where a stone was mined. Sources of verdelite include Brazil, Afghanistan, Mozambique, and the United States.

Value

Green tourmalines in mint, teal, and other light green shades have gone up in value. While there’s no guarantee, I personally believe they will continue to do so.

Collectability

Collectors seek out quality, large-sized stones in light green colors.

verdelite - California
“Tourmaline (Var. Verdelite),” Cota Mine, Gem Hill, Mesa Grande District, San Diego Co., California, USA. © 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.