Tourmaline Buying Guide


tourmaline buying - maleficent pendant
“Maleficent Pendant” featuring a blue and green tourmaline crystal. © Sam Woehrmann. Used with permission.

Known for stunning, saturated hues, tourmaline is a colorful and modern gemstone. This October birthstone is hard enough and durable enough for everyday jewelry wear. Most tourmalines undergo heat and radiation treatments to achieve these hues. However, these procedures have stable results. With so many varieties and colors, you can always add more tourmalines to your collection.

Tourmaline Buying and the Four Cs

The IGS tourmaline value listing has price guidelines for Paraíba tourmalines, indicolite, rubellite, chrome tourmalines, and other colors of faceted stones, as well as cat’s eye and non-phenomenal cabochons.

Color

Tourmalines come in all the colors of the rainbow. When buying tourmaline of any color, view it under several different types of lighting, as most gems will exhibit some alteration in color or decreased saturation in incandescent light.

tourmaline buying - bracelet with several tourmaline colors
This Autumn colored tourmaline bracelet features a few of tourmaline’s colors. © Sam Woehrmann. Used with permission.
Blue

In tourmalines, blue and blue-green hues arise from iron or copper in the crystal structure. While rare, blue hues are also the most popular color of this gemstone.

Indicolite is the gemological name for blue tourmalines. Generally, this term refers to tourmalines colored by iron. Indicolites can be greyish blue, blue, or blue-green. The most costly gems exhibit medium tones and saturated color. Since indicolites commonly receive heat and radiation treatments, ask about treatments before purchasing. If you’re interested in indicolites, read the indicolite buying guide.

tourmaline buying - 2.12ct Afghani blue tourmaline
2.12-ct blue tourmaline. Though this gem is not copper-bearing, its color rivals the finest Paraíba tourmalines. © JL White Fine Gemstones. Used with permission.
Paraíba

In 1989, a new variety of tourmaline came out of Brazil. This material, called “Paraíba tourmaline” for the Brazilian state of Paraíba, displays an electric blue to blue-green hue due to the presence of copper. Before the discovery of this variety, tourmaline colors were valued primarily on how well they simulated better-known rubies, emeralds, and blue sapphires. Now, more people recognize and appreciate tourmalines for their eye-popping saturation.

While this variety was named for its original locality, mines in other countries have produced copper-bearing tourmalines. These have entered the market as “Paraíba tourmaline.” Major gem laboratories can determine the origin of the stone, and this testing is recommended for any stone sold as Brazilian in origin. While quality Paraíba tourmalines also occur in other localities, such as Nigeria and Mozambique, Brazilian stones hold much higher value.

Like indicolite, medium tones and saturated color are the hallmarks of a top-quality Paraíba tourmaline. Hue should be blue, sometimes with very slight green hues. Significant green hues will detract from the price.  Dark-toned specimens often undergo heat treatment to lighten them.

tourmaline buying - Mozambique paraiba tourmaline ring
Paraíba tourmaline and golden beryl with white and colored diamonds. “Mozambique” © Kathleen Dughi Jeweler. Used with permission.
Green

Verdelite, or green tourmaline, is a variety of elbaite that has primary green hues. The most common color of gem-quality tourmaline, green tourmalines occur in yellow-green, green, and blue-green hues. Of these, the stones that come closest in color to fine emerald, with medium-dark tones and slight secondary blue hues, and those that imitate blue-green Paraíba tourmalines, with intense saturation and medium tones, hold the highest value. Light tones, such as mint greens, also enjoy some popularity. The verdelite buying guide has more information on what to look for in green tourmalines.

tourmaline buying - neon kite ring
16.61 ct neon green kite-cut tourmaline. © Ben Day Jewelers. Used with permission.
Chrome

Some green tourmalines contain chromium and/or vanadium, which imparts a lovely green hue. The same elements color tsavorite garnets and emeralds, so, unsurprisingly, fine chrome tourmaline color resembles high-quality emerald green. These gems tend to have strong saturation and pure green to slightly bluish green hues. Yellow hues hold less value.  For more information, look at the chrome tourmaline buying guide.

tourmaline buying - Eclipse earrings with chrome tourmaline posts, canary diamond, ammolite
“Eclipse” earrings with chrome tourmaline, canary diamonds, and ammolite. Photo by IGS Creative. Part of the KORITE Ammolite Designer Collection. © Martha Seely. Used with permission.
Pink

Rubellite is a loose term that refers to tourmaline gems in the deep pink to red range. Although the comparison to ruby is tempting, it’s not entirely accurate. Considering how tourmaline color can alter under different lighting sources, a rubellite with a fine red, ruby-like day hue may dull in incandescent light, or this lighting will bring out secondary purple hues.  While undesirable in ruby, the shift to purplish hues is much more attractive in rubellite than a shift to a muddied red.

tourmaline buying - rubellite ring
18k gold ring with a rubellite tourmaline and fine white diamonds. © Ben Day Jewelers. Used with permission.

Perhaps the finest rubellite colors are the raspberry hues. These gems show slight to moderate secondary purple hues and the eye-catching saturation that make tourmaline a prized stone. The rubellite buying guide has more information on these gems.

Pale pink hues of elbaite, though not rubellite, can have beautiful shades for more reserved jewelry pieces.

tourmaline buying - Ciotollo pink tourmaline bracelet
Bracelet with many hues of pink tourmaline, accented with diamonds. “Ciotollo” © Kathleen Dughi Jeweler. Used with permission.
Other Colors

Yellow, orange, and purple hues of tourmaline are very rare. When evaluating the price of these colors, keep in mind that purer hues generally hold higher prices. For example, a lemon-yellow gem without a greenish tinge or slight orange hue is more valuable than an off-color stone.

tourmaline buying - 5.00 ct orange
5.00-ct orange Kenyan tourmaline. © Earth’s Treasury. Used with permission.

Affordable brown tourmalines occur in a range of hues, including chocolate and cognac.

Although inexpensive, black tourmaline can add a sophisticated look to a jewelry piece.

Bi-colored and Parti-colored Tourmalines

Changes in chemical composition during tourmaline formation create differences in hue within the gem. As a result, many tourmaline crystals exhibit two or more chromatic hues along the crystal. Most commonly, a combination of green and pink is present. A gem that exhibits intense hues with a drastic transition between colors will fetch a better price than one with a slower or muddied transition. The relative sizes of the colors also affect the prices of these gems. The best gems have even amounts of each color.

tourmaline buying - 13.57 ct blue and pink bi-color tourmaline
A 13.57- ct blue and pink tourmaline – a rare and highly sought color combination. © JL White Fine Gemstones. Used with permission.
Watermelon Tourmaline

Generally, tourmaline color changes along the length of the crystal.  However, for watermelon tourmalines, the color changes radially outward.  Here, the inside of the crystal is pink and the outside green, resembling a watermelon. These gems are often cut in slices to mimic the fruit.

tourmaline buying - watermelon tourmaline
A tri-colored slice of watermelon tourmaline (note the thin layer of colorless crystal between the green and pink areas). “Watermelon tourmaline” by Mauro Cateb. Licensed under CC By 2.0.

Clarity

Tourmaline clarity expectations differ based on color. For verdelites, the most common color, eye-clean gems are readily available, and loupe-clean verdelites are not difficult to obtain. Clarity for chrome tourmalines is similar to verdelites. However, eye-clean rubellites are less common.  For indicolites and Paraíba tourmalines, eye-clean specimens are rare and hold very high value.

tourmaline buying - sea ring
This 79.80-ct indicolite has inclusions that make it appear like the wind-blown sea. © Ben Day Jewelers. Used with permission.

Tourmalines that exhibit multiple chromatic hues are more likely to have inclusions and fractures. This is due to changes in their chemical composition during their formation.

Some tourmalines exhibit chatoyancy, or a cat’s eye effect, due to hollow tube-like inclusions. When properly cut, these are delightful!

tourmaline buying - cat's eye ring
Blue cat’s eye tourmaline stack of rings, 22k yellow gold, 14k rose gold, and sterling silver. © Sam Woehrmann. Used with permission.

Cut

Dark, highly saturated rough can benefit from brilliant and checkerboard cuts. For lighter rough, any cut can work. As always, be sure that the cut is symmetrical and correctly proportioned.

tourmaline buying - 3.94 ct magenta-peach brilliant cut
A 3.94 bi-color magenta and peach tourmaline, cut so that the magenta region is in the middle of the stone and peach hues at the side. Faceted in a mixed round brilliant/step design by Peter Torraca. © Earth’s Treasury. Used with permission.

Due to their crystal structure, many tourmalines are cut into long, narrow posts to retain weight or to exhibit the colors in a bi-color or parti-color stone.

tourmaline buying - 6.67ct bicolored tourmaline
This intensely bicolored 6.67-ct tourmaline from the Himalaya Mine in Mesa Grande, California has an enlongated cut common in tourmalines. © Earth’s Treasury. Used with permission.

Carat

Easily available sizes differ by the color of tourmaline. Nevertheless, you can find tourmalines of any color in any size. For example, verdelites and rubellites are readily available in sizes up to six carats. However, anything over 15 carats in these gems will require some searching.

Chrome tourmalines tend to be smaller, with sizes under two carats the most common and anything above eight carats much rarer.

For indicolite, any size is rare and will fetch a good price. Paraíba tourmalines from Brazil are rare in any size, but most rough from this locality produced gems under two carats. On the other hand, Paraíba material from Mozambique is much larger, up to 20 carats.

tourmaline buying - rough and cut set
A set of rough (4.2 cm long) and cut (49.9 ct) tri-color tourmaline. © Rob Lavinsky, www.iRocks.com. Used with permission.

Dichroism: The Multicolor Effect

Tourmalines are highly dichroic, shifting hue depending on the viewing angle. This creates a spectacular effect where adjacent facets may show entirely different hues. While undesirable in traditional emeralds, rubies, and sapphires, this effect can be very attractive in tourmalines. It can give the stone a unique sparkle.

This gem has strong dichroism, with bright pink and peach tones visible.  © JL White Fine Gemstones.  Used with permission.

Gemstone Treatments

Most tourmalines receive heat treatment. Some also undergo radiation treatment. Unfortunately, since these create stable colors, vendors often don’t disclose them to consumers. Always ask about treatments before purchasing a tourmaline, and assume that any tourmaline has been heat-treated.

Pink, red, and blue tourmalines commonly receive heat and radiation treatments. Green tourmalines are sometimes heated to lighten their color. However, this treatment often doesn’t produce a desirable color. Still, it’s best to assume that a tourmaline was heat treated.

Simulants

Synthetic tourmalines are expensive and difficult to manufacture, even in very small sizes. Thus, they aren’t commercially available. Dyed quartz, glass, or other synthetic stones, such as synthetic spinel, are sometimes presented as simulants for tourmaline.

About the author
Addison Rice
A geologist, environmental engineer and Caltech graduate, Addison's interest in the mesmerizing and beautiful results of earth's geological processes began in her elementary school's environmental club. When she isn't writing about gems and minerals, Addison spends winters studying ancient climates in Iceland and summers hiking the Colorado Rockies.
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