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: Chrome Tourmaline Info

Chrome Tourmaline Gemstone Information

About Chrome Tourmaline - History and Introduction

Chrome tourmaline is a rare, gemstone quality variety of chromium-bearing green dravite. Dravite is one of several specific varieties of the tourmaline group. Although dravite tourmaline is quite common in occurrence, most deposits are too opaque or too heavily included to be of any gemstone value. Chrome tourmaline, or chrome dravite, owes its color to traces of chromium, the same element responsible for red ruby and green emerald. It may also contain vanadium, another coloring agent commonly found in both emerald and tsavorite garnet. Chrome tourmaline is highly-prized for its distinct, rich forest-green color and is considered a collector's gem, but not because it lacks the hardness and durability for jewelry, but because of its extreme rarity in occurrence.

Unlike other varieties of tourmaline, chrome tourmaline is rarely found in large sizes, in fact, most stones weigh less than a single carat. Chrome tourmaline is found only in Tanzania and is often associated with green tsavorite garnet, a very rare and valuable variety of garnet. Tsavorite is also found solely in Tanzania and is often mined from the very same location as chrome tourmaline. Contrary to most beliefs, there are surprisingly very few gemstones that naturally occur in green; subsequently, even fewer colored by chromium. The color of chrome tourmaline is said to rival that of the finest emerald and tsavorite, but is much more affordable. Its color is also similar to chrome diopside, another chromium-rich gemstone, but tourmaline is significantly harder and much more durable for jewelry use.

Chrome Tourmaline

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Identifying Chrome Tourmaline Back to Top

Chrome tourmaline can be easily distinguished from other varieties of green tourmaline by the presence of chromium. Testing for chromium content is typically done using a specialized filter, known as a 'Chelsea filter'. A Chelsea filter will show flashes of red or orangey red when viewing chromium-rich stones. In many cases, scratch testing can help identify chrome tourmaline among other similar green materials, such as chrome diopside, sapphire and spinel. It is considerably softer than sapphire and spinel, but significantly harder than any diopside.

Tourmaline crystals are doubly refractive to a high degree, which can help with identification. Chrome tourmaline crystals are long, columnar and trigonal, and typically triangular in cross-section. It is through these distinct three-sided prisms that chrome tourmaline can be easily distinguished, simply because no other commonly occurring mineral is known to exhibit such distinct three-sided forms as tourmaline.

Chrome tourmaline has a unique ability to carry a small electrical charge when subjected to mechanical stress, pressure or extreme temperature fluctuations. These properties are referred to respectively as piezoelectricity and pyroelectricity, and in many cases, can be so pronounced that crystals can even attract small bits of paper, straw or wood. Piezoelectricity and pyroelectricity are fascinating properties that are known to exist in only a handful of different types of gems, which include rare axinite, prehnite and also in chalcedony quartz.

Chrome Tourmaline Origin and Gemstone Sources Back to Top

Chrome tourmaline is found only in Tanzania, which is also the world's only source for tanzanite and tsavorite. Chrome tourmaline and tsavorite are often sourced from the same mines, but miners tend to focus more on tsavorite, owing to its higher profitability. Tanzania is also very well-known for its abundance of fine sapphire, spinel, zircon, chrysoberyl and chrysoprase.

Buying Chrome Tourmaline and Determining Chrome Tourmaline Gemstone Value Back to Top

Chrome Tourmaline Color

Chrome tourmaline occurs with an attractive, medium-rich, forest-green color. The primary green color is often accompanied by secondary hues of either yellowish or bluish tones. Blue hues are best viewed under incandescent light, whilst yellows are best viewed under daylight. Bluish materials are considered more valuable, and unlike emerald, there can never be too much blue in chrome tourmaline.

Chrome tourmaline color tends to darken with larger stones, often exhibiting near-blackish tones. Some specimens may even appear opaque. The color is deepest along the main axis of tourmaline crystals, which means that precise orientation of cut is required in order to achieve the optimum color. Chrome tourmaline exhibits a remarkable level of dichroism, which means a single stone reflecting two or more different colors, or depths of color and color intensity, depending on the angle from which it is viewed.

Chrome Tourmaline Clarity and Luster

Most tourmaline gemstones are naturally included and typically found with visible fractures and needle-like inclusions, but chrome tourmaline is prized for its excellent transparency and is typically found with very few inclusions, most often being eye-clean. Chrome tourmaline has an extremely attractive, vitreous to slightly resinous luster once cut and polished.

Chrome Tourmaline Cut and Shape

Chrome tourmaline is strongly dichroic, making the quality of cut very important in order to highlight the best and lighter of colors. This is done through the careful orientation of cut. In order to achieve the best color, the table facet must be cut perpendicular to the c-axis, which commonly results in shapes such as long bars, baguettes and octagon or emerald cuts.

Other common shapes include cushion, round, oval, pear and triangular (trillion) shapes. These shapes tend to bring out the best in color, while also maximizing the rough carat weight. Chrome tourmaline is most often faceted to bring out color and brilliance, but on occasion, it may be cut en cabochon (typically only lower grade materials).

Chrome Tourmaline Treatment

Chrome tourmaline is not known to be heated, treated or enhanced in any way. In fact, most tourmaline is completely unenhanced. However, some specific varieties of tourmaline may occasionally be heated or irradiated to improve color and clarity.

Chrome Tourmaline Gemological Properties: Back to Top
Chemical Formula: (Ca,K,Na,[]) (Al,Fe,Li,Mg,Mn)3 - Cyclosilicate
Crystal Structure: (Trigonal) long crystals with triangular cross-section and rounded sides.
Color:

Light-green to dark-green; secondarily bluish, yellowish, reddish

Hardness: 7 to 7.5 on the Mohs scale
Refractive Index: 1.614 to 1.666
Density: 2.82 to 3.32
Cleavage: Indistinct - fracture: uneven, small conchoidal, brittle
Transparency: Transparent, translucent, opaque
Double Refraction or Birefringence: -0.014 to -0.032
Luster: Vitreous to slightly resinous
Fluorescence: Weak to none

Please refer to our Gemstone Glossary for details of gemology-related terms.

Chrome Tourmaline: Varieties or Similar Gemstones: Back to Top
Cat's Eye Tourmaline
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Chrome tourmaline belongs to the vast group of tourmaline gemstones. The tourmaline family includes a variety of different gemstones with slightly different chemical compositions, and each with their own specific trade name. Many of the trade names used today are simply based on variations of color, or are locality-based names, which aren't 'officially-recognized' names, but are used only by the most avid of gem and mineral collectors.

Synonyms for chrome tourmaline include chromium tourmaline and chromtourmaline (as well as various alternative spellings). The tourmaline family consists of several specific groups: Elbaite, schorl, dravite, liddicoatite, uvite, chromdravite and buergerite. Most of the gem-quality tourmaline available today is a variety of elbaite tourmaline, but chrome tourmaline is an exceptionally rare variety of dravite.

Most Popular Similar or Related Gemstone Varieties and Trade Names:

Paraiba tourmaline), rubellite tourmaline), indicolite, cat's eye tourmaline, canary tourmaline, watermelon tourmaline, pink tourmaline and bi-color tourmaline are some of the most popular trade names of similar or related gems and minerals.

Lesser-Known Similar or Related Gemstone Varieties and Trade Names:

Buergerite, dravite (brown), liddicoatite, uvite, tsilasite, elbaite, verdelite (green), siberite (purple), achroite (colorless) and schorl are some of the lesser known trade names of similar or related gems and minerals.

Chrome Tourmaline Gemstone Mythology, Metaphysical and Alternative Crystal Healing Powers Back to Top

There are various legends, as well as lore, metaphysical powers and beliefs attached to the vast group of tourmaline crystals, all of which include the specific variety of chrome tourmaline as well. Chrome tourmaline may be worn as an official birthstone for October. For those fortunate enough to celebrate their 8th year of marriage, chrome tourmaline may also be worn as an anniversary stone.

Chrome tourmaline is a stone of Sagittarius (the archer), and is the planetary stone for Jupiter. It is thought to be ideal for balancing the element of fire. Chrome tourmaline may also benefit all chakras, as it is an excellent base and grounding stone. Since most chrome tourmaline exhibits more than one color, it can balance many chakras and elemental forces. Tourmaline is said to be especially powerful for friendships and love. Physically, chrome tourmaline can help the immune system and alleviate pains associated with heart disease, arthritis and gout. It can also help those who suffer from anxiety and grief, by dispelling their fears and relaxing both the body and mind.

Disclaimer: Metaphysical and Alternative Crystal Healing Powers and Properties are not to be taken as confirmed advice. Traditional, Ceremonial and Mythological Gemstone Lore is collected from various resources and is not the sole opinion of SETT Co., Ltd. This information is not to replace the advice of your doctor. Should you have any medical conditions, please see a licensed medical practitioner. GemSelect does not guarantee any claims or statements of healing or astrological birthstone powers and cannot be held liable under any circumstances.
Chrome Tourmaline Gemstone and Jewelry Design Ideas Back to Top

Chrome tourmaline, like all varieties of tourmaline, is absolutely ideal for any type of jewelry design imaginable. Chrome tourmaline is hard, durable, affordable and extremely versatile. However, unlike other varieties of tourmaline stones, chrome tourmaline is typically available only in small sizes, making it best suited for smaller gem accessories, such as small rings, earrings or small pendants. Matching pairs and lots of chrome tourmaline can be very hard to source, so matching earrings may be difficult to create without custom cutting.

Note: Buy colored gemstones by size and not by carat weight. Colored stones vary in size-to-weight ratio. Some stones are larger and others are smaller than diamond by weight in comparison.

Chrome Tourmaline Gemstone and Jewelry Care and Cleaning Back to Top

How to clean your gemstonesChrome tourmaline is considered to be one of the most durable gemstones available. It requires very little care and maintenance, however, owing to its unique ability to carry a small electrical charge, it tends to attract more dust than most other gems. Therefore, because of its pyro- and piezoelectric properties, chrome tourmaline will likely require a routine wipe-down. It is recommended that a simple soft cloth and warm soapy water is used for this. Be sure to rinse stones well to remove soapy residue. Although tourmaline in general is considered quite hard and durable, avoid wearing it when working with any harsh chemicals or cleaners, especially bleach and sulfuric acid. As with all gems, always remove any chrome tourmaline jewelry before playing sports, exercising or performing any vigorous household chores, such as dishwashing

Do not use ultrasonic cleaners and steamers, and it is best to avoid extreme heat, including prolonged exposure to direct sunlight. To prevent scratches to your gems, keep your gemstones and jewelry away from one another when cleaning and wearing them, and if possible, always store them separately from each other. If possible, wrap your gems and jewelry in a soft cloth or place them inside a fabric-lined jewelry box for added security.

  • First Published: November-28-2013
  • Last Updated: October-12-2017
  • © 2005-2017 GemSelect.com all rights reserved.
    Reproduction (text or graphics) without the express written consent of GemSelect.com (SETT Company Ltd.) is strictly prohibited.
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Size and Weight

Gems are always measured in Millimeter (mm)

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length x width x depth,
except for round stones which are;
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Select gems by size, not by weight!
Gem varieties vary in density, so carat weight is not a good indication of size

Note: 1ct = 0.2g

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