North Carolina the State Mineral

North Carolina State Mineral
Spodumene STATUS Unofficial DESCRIPTION Spodumene is a lithium aluminum silicate mineral and a lithium ore. Spodumene occurs as white, colorless, gray, pink, violet, green, yellow, or brown, and may have pleochroism, meaning it can display more than one color when viewed at different angles. Spodumene occurs as transparent to translucent. This mineral was only discovered in the last several centuries, and its gem varieties in the last century, making this mineral relatively new to mineralogy and gemology. STATE SYMBOL Hiddenite is a gem quality variety of spodumene. Only green spodumene from Alexander County, North Carolina, is gemologically accepted as true hiddenite. Prized in the gem trade, hiddenite is not a very well known or abundant mineral. In about 1879, exploration geologist William Earl Hidden first discovered this mineral. Hiddenite was named in his honor. Until the last domestic mine closed in 1998, spodumene was the major raw material used for the production of lithium carbonate in North Carolina, and small amounts of spodumene concentrate also were produced for sale. North Carolina does not have an official state mineral, but spodumene and its gem variety hiddenite are representative of the state’s geology, history, and economy. NAME ORIGIN The word spodumene comes from the Greek σποδυμενος, which means "burned to ashes," referring to the color of the mineral’s non-gem variety used in industry. FORMATION AND OCCURRENCE Spodumene is a characteristic mineral of lithium-rich granite pegmatites. It forms long, flat prisms or rectangular crystals. It is a member of the pyroxene group, a large group of chain silicate minerals that form rocks. Spodumene occurs in association with topaz, tourmaline, quartz, lepidolite, and plagioclase feldspars. GEOGRAPHIC DISTRIBUTION Many localities for spodumene are known; not all are listed here. Sweden: Utö, Södermanland; and in the Varuträsk pegmatite, near Skellefteå, Västerbotten Finland: Kuortane, and the Tammela district United States: Etta mine, near Keystone, Pennington County, South Dakota; elsewhere in the Black Hills, South Dakota; Hiddenite, Alexander County, North Carolina; Foote mine, Kings Mountain, Cleveland County, North Carolina; Pala district, San Diego County, California; and Harding mine, Dixon, Taos County, New Mexico Canada: Tanco mine, Bernic Lake, Manitoba Brazil: Urupuca mine, Itambacari; and Resplendor, Minas Gerais Afghanistan: Mawi and Kantiva, Nuristan district, Laghman Province Madagascar: Maharitra, Mt. Bity; and Anjanabonoina Zimbabwe: Bikita USES Spodumene is an ore of lithium. Lithium is used in pharmaceuticals, ceramics, and batteries for mobile phones and automobiles. Lithium is also used as an industrial flux, or agent added to a liquid to improve its flow. Although not particularly well known, two varieties of spodumene are prized as gemstones. The pink to violet gem variety owing its color to manganese impurities is called kunzite, and the green to yellow-green gem variety, colored by chromium, is named hiddenite. Both these gem varieties are highly sought after for their transparency, unique colors, and pleochroism. After several years in prolonged sunlight, however, kunzite’s color can fade from bright to colorless. In the gem trade, spodumene refers to all other, less desirable colors of this mineral. The fracture and cleavage of these gems present challenges for gem cutters. To display the best color, gem cutters must cut large stones and present the gems in the correct position. Kunzite was named in honor of Tiffany & Co.’s head jeweler, George Frederick Kunz, a legendary American mineralogist. The mineral was first discovered in Pala, California, in 1902. Kunzite has been said to improve personal relationships. FAMOUS EXAMPLES The Etta mine in Keystone, South Dakota, produces giant spodumene crystal logs up to 46 feet (14 m) in length. One of the largest known gem-quality kunzite crystals was found at the Itambacari Mine in Urupuca, Brazil. It now resides at the National Museum of Natural History in Washington, D.C. President John F. Kennedy purchased a kunzite ring as a gift for his wife Jacqueline in 1963. Twenty round diamonds surround the 47-carat oval kunzite stone. Kennedy’s untimely death interceded, and he was never able to present the ring to his wife. This ring sold for more than $410,000 at the 1996 Sotheby’s auction of the estate of Jacqueline Kennedy Onassis.	Spodumene and Quartz Spodumene Specimen Smoky Spodumene Crystal  Pale Blue Spodumene Crystal Kunzite Necklace, Courtesy of the Smithsonian Institution SPODUMENE FACTS Group: Pyroxene  Chemical Formula: LiAl[Si2O6] Crystal Structure: Monoclinic Hardness (Mohs): 6½-7 Color: Colorless, yellow, light green, emerald-green, pink to violet, purple, white, gray Transparency: Transparent, translucent Luster: Vitreous, dull Density: 3.1-3.2 g/cm3 Streak: White Cleavage: Perfect Fracture: Sub-conchoidal
	Some data courtesy of the Mineralogical Society of America Author: World Trade Press