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The Gemstone Diopside

Diopside has been regarded only as a collector's gemstone until recently, when the deep forest-green Chrome Diopside variety has made its way into the mainstream gemstone market. Although its intense green color rivals that of Emerald, its low hardness makes it prone to scratches, thus limiting it from overwhelming the gemstone industry.

Color

Green, Yellow, Brown, Black

Hardness

5 - 6

Chemical Formula

CaMgSi₂O₆

Mineral Class

Diopside

Additional Properties

Crystal System
Monoclinic

Refractive Index
1.665 - 1.730

Double Refraction
0.028

Transparency
Transparent. Star Diopside is opaque.

SG
3.3 - 3.5

Luster
Vitreous

Cleavage 1,2 - prismatic. May also exhibit parting in one direction.

All About

Although Diopside occurs in a variety of colors, the green color is the most common form. A purple type known as Violane is occasionally used as a gemstone, and Star Diopside is very dark green to black. But the form of this stone that puts this gemstone on the map is the deep green Chrome Diopside form.

Chrome Diopside in limited quantity is known from several localities, but a large commercially exploitable deposit discovered in Siberia in 1988 made this gemstone readily available to the market. Since then, Pakistan has also become a signficant producer of Chrome Diopside. Chrome Diopside is an affordable gemstone that has an intense forest-green color which rivals that of more expensive Tsavorite and Green Chrome Tourmaline.

Deep green color combined with transparency give a stone more value. Except in lighter colored stones, the faceting of larger cuts is generally avoided because the deep green color tends to make its tone too black. Careful cutting is also necessary in larger stones to keep the facet angles shallow to improve brilliance. The deep green color of Chrome Diopside is natural and not enhanced.

Uses

Chrome Diopside is faceted into gemstone cuts mainly for earrings and pendants. It is generally not used for rings and bracelet due to its low hardness. Star Diopside and the purple variety Violane are faceted into cabochons mostly as collectors gems.

Varieties

Chrome Diopside - Deep forest-green variety of Diopside. Its color is caused from traces of the element chromium.
Star Diopside - Diopside polished into a cabochon that displays asterism in the form of a four-rayed star. Its colors is usually very dark green to black.
Tashmarine Diopside - Light yellowish-green form of Diopside from a recently exploited deposit in eastern Uzbekistan. This term was recently coined by the Columbia Gem House company in Vancouver.
Violane - Light blue to purple, manganese-rich variety of Diopside.

Treatments & Enhancements

Diopside gemstones are natural and not heated or enhanced.

Diopside Sources

Diopside of facetable nature comes from Italy, Austria, Finland, Tanzania, Madagascar, Mynamar (Burma), China, and the U.S. (New York). The source of most gem is from Russia, but other deposits also exist in Pakistan, Afghanistan, and Finland. Violane is primarily from Italy, and Star Diopside from India.

Similar Gemstones

Chrome Diopside has a similar color to both Tsavorite and Chrome Tourmaline, but is softer than those gemstones. The color is also a more forest-green hue than Emerald.