Spodumene is a Lithium Aluminum Silicate mineral (LiAlSi2O6). It comes in the varieties of Kunzite, Hiddenite, and Triphane. It will be appear as a working ore of lithium. Spodumene constituents of lithium-rich granite pegmatites. It is usually in association with other lithium minerals such as lepidolite, eucryptite, and petalite. Spodumene can form crystals to 14 meters (47 feet) in length. The mineral is a member of the Pyroxene Group of minerals.
Characteristics of Spodumene
The mineral belongs to the Monoclinic Crystal System, Prismatic class. It’s Hardness is 6.5 – 7 on the Moh’s Scale. The mineral’s luster is vitreous to silky. Spodumene may fluoresce white to blue in shortwave, and dark orange to orange-red in long-wave.
Spodumene will often be in display as long, flat, prismatic crystals. It is also found as rectangular crystals, tabular, bladed, and elongated crystals, as well as cleavage fragments, and massive. Crystals are usually striated lengthwise, sometimes deeply. Spodumene is rarely seen on a matrix as it easily pops out of the host rocks. Because of their rarity, matrix specimens are highly sought after. Spodumene easily alters to other minerals (most often to feldspars and micas), and into clay. Sometimes, a crystal may be only partially altered, creating fascinating and intriguing specimens.
The color spectrum of Spodumene
Spodumene is strongly pleochroic. Observing pleochroism is easy with many transparent crystals, where the color ranges from yellow to violet when viewed at different angles. Pink Kunzite will often exhibit a deeper pink color on crystal terminations due to the pleochroism.
Spodumene occurs in many colors including white, colorless, gray, pink, violet, green, yellow, brown. Sometimes, Spodumene occurs in transparent crystals in pastel shades of pink, purple, green, and yellow. These crystals have been cut into gemstones that are prized by collectors. However, their use in jewelry is constraint to pieces that will be subject to limited abuse because of spodumene’s perfect cleavage.
Varieties of Spodumene
Pink to lilac specimens of gem-quality spodumene are high prizes as “Kunzite”. The color of these specimens is because of the presence of manganese as a chromophore. Kunzite is the most common gem variety of spodumene.
“Hiddenite” is the name of the emerald-green spodumene. Its vivid green color is very similar to emerald and is due to the presence of chromium as a chromophore. It is the rarest gem variety of spodumene. This variety was first found near the town of White Plains, North Carolina, which changed its name to “Hiddenite” after the popular gemstone that attracted people to the area.
Spodumene rarely occurs in a yellow color. However, some yellow spodumene can be of gem quality, and it has often cut into facets and cabochon gems. These gems will be “Triphane”.
Some gem-quality spodumene will develop a richer color when heated or irradiated. This procedure will be part of many gems that enter the marketplace. Some of these will fade over time when exposed to direct sun light. Best storage of valuable spodumene gems of any color should be away from direct light.
Spodumene is an important source of lithium. Lithium has many diverse uses. It exists in manufacturing rechargeable batteries, ceramics, specialty glass, high-temperature grease, polymers, casting flux, aluminum alloys, and pharmaceuticals.
Noteworthy Localities
For gem collectors, the most exceptional crystals come from the famous pegmatites of Afghanistan in the Konar Valley; Paprok in Nuristan Province; and at the Mawi and Darra-i-Pech pegmatites in Laghman Province. Other important worldwide locations are Galiléia and Resplendor, Doce valley, in Minas Gerais, Brazil; Ampatsikahitra, Sahatany Valley, Madagascar; and Alto Ligonha, Zambezia Province, Mozambique.
The United States has several important Spodumene locations. Outstanding Kunzite comes from the Pala District of San Diego County, California, where this gem variety was first identified. Specific noteworthy claims in Pala include the Pala Chief Mine, the Oceanview Mine (especially the “Big Kahuna Pocket” of 2009-2010), the Elizabeth R. Mine, the Vanderberg Mine, the Katerina Mine, and the San Pedro Mine. Another Kunzite location in San Diego County is the Beebe Hole Mine, in Jacumba. Hiddenite is famous at the localities of Hiddenite and Stony Point in Alexander County, North Carolina.
There are also some well-known Spodumene localities in New England, specifically Newry, Oxford County, Maine; Branchville, Fairfield County, Connecticut; and the Strickland Quarry, Portland, Middlesex County, Connecticut. Large white well-terminated crystals once came from Hampshire County, Massachusetts at both Walnut Hill in Huntington; and at the Barrus Farm in Goshen.
Other well-known U.S. Spodumene deposits include the Foote Lithium Mine, Kings Mountain, Cleveland County, North Carolina; the Etta Mine, Keystone, Black Hills, Pennington County, South Dakota; and the Harding Mine, near Dixon, Taos County, New Mexico.
World production of lithium via spodumene in 2018 was for the most part from the Greenbushes pegmatite of Western Australia and from some Chinese and Chilean sources. The largest spodumene deposit is in Manono, Tanganyika Province, Democratic Republic of Congo.
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Article by Bill Jones, Sidewinder Minerals
