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The Gemstone Spodumene

Spodumene is a mineral that contains two important gem varieties: pink Kunzite and green Hiddenite. Both of these gemstone varieties have their own dedicated page. In the gem trade, the term Spodumene is generally used to include only the yellow, brownish, light greenish, and colorless forms of Spodumene.

Color

White, Colorless, Blue, Green, Yellow, Orange, Brown, Pink, Purple, Gray, Multicolored

Hardness

6.5 - 7

Chemical Formula

LiAlSi₂O₆

Mineral Class

Spodumene

Additional Properties

Crystal System
Monoclinic

Refractive Index
1.66 - 1.68

Double Refraction
.015

Transparency
Transparent

SG
3.1 - 3.2

Luster
Vitreous

Cleavage 1,2 - prismatic

All About

Most gemstones labeled as Spodumene are of the yellow type; brown and colorless gems are seldom faceted. A rarity is the faint blue to bluish-green variety, as well as multicolored forms.

In a strict sense, the term Hiddenite refers specifically to the green, transparent Spodumene variety originating in Alexander Co., North Carolina, whereas all other green Spodumene is known simply as "Green Spodumene". However, the name Hiddenite has been corrupted by the gem and mineral industry to include all green gem Spodumene from other localities. Chromium impurities are responsible for the green color in North Carolina Hiddenite; the other localities generally produce lighter colored and more yellowish in tone, and lack the chromium.

The perfect cleavage and splintery fracture of Spodumene gemstones make them difficult to facet. They are very sensitive to knocks and will chip if hit too hard. Spodumene is also strongly pleochroic, showing lighter and more intense coloring when viewed at different angles. Brown Spodumene is sometimes heat treated to transform the color into a more pink tone and produce Kunzite.

Uses

With the exception of Kunzite and Hiddenite, other color forms of Spodumene are not commonly used as gems. However, the yellow form has started gaining a bit in popularity is is faceted into gemstone cuts. Other color forms are seldom faceted.

Varieties

Hiddenite - Green chromium-rich transparent variety of Spodumene. Originally used only to describe green Spodumene from the Hiddenite area in North Carolina, this term is commonly also used referencing other green forms from Afghanistan and Brazil.
Kunzite - Pink to violet transparent variety of Spodumene.
Triphane - Colorless to yellow transparent variety of Spodumene.

Treatments & Enhancements

Some forms of Kunzite may be heat treated to remove undesirable brownish tints and increase transparency.

Spodumene Sources

The main source of gem-quality Spodumene is Afghanistan; other sources are Pakistan, Brazil, Madagascar, Mozambique, and the U.S. (California, and Maine).

Similar Gemstones

Yellow Spodumene resembles yellow Beryl and ,but is lighter in hardness. It also can be similar to yellow Topaz and yellow Citrine ("Lemon Quartz"), but is usually lighter in tone and slightly softer.