- Nahcolite
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Nahcolite General Category Mineral Chemical formula NaHCO3 Strunz classification 05.AA.15 Dana classification 13.01.01.01 Identification Colour White to colourless, may be grey to brown Crystal habit Elongated crystals, fibrous masses, friable porous aggregates Crystal system Monoclinic prismatic Twinning Common on [101] Cleavage {101} perfect, {111} good, {100} distinct Fracture Conchoidal Tenacity Brittle Mohs scale hardness 2.5 Luster Vitreous - resinous Streak White Diaphaneity Transparent to translucent Specific gravity 2.21 Optical properties Biaxial (-) Refractive index nα = 1.377 nβ = 1.503 nγ = 1.583 Birefringence δ = 0.206 Ultraviolet fluorescence Short UV=blue-white cream-yellow, Long UV=cream-yellow References [1][2][3] Nahcolite is a soft, colourless or white carbonate mineral with the composition of sodium bicarbonate (NaHCO3) also called thermokalite. It crystallizes in the monoclinic system.[3]
Nahcolite was first described in 1928 for an occurrence in a lava tunnel at Mount Vesuvius, Italy.[1] The name is in reference to its chemical formula. It occurs as a hot spring and saline lake precipitate or efflorescence; in differentiated alkalic massifs; in fluid inclusions as a daughter mineral phase and in evaporite deposits.[1][3] Its name refers to the elements which compose it: Na, H, C, and O.[4]
It occurs in association with trona, thermonatrite, thenardite, halite, gaylussite, burkeite, northupite and borax.[2] It has been reported in a Roman conduit at Stufe de Nerone, Campi Flegrei, near Naples; in the U. S. from Searles Lake, San Bernardino County, California; in the Green River Formation, Colorado and Utah; in the Tincalayu deposit, Salar del Hombre Muerto, Salta Province, Argentina; on Mt. Alluaiv, Lovozero Massif and Khibiny Massif, Kola Peninsula, Russia; and around Mount Erebus, Victoria Land, Antarctica.[2]
References
- ^ a b c Mindat Data sheet
- ^ a b c http://www.handbookofmineralogy.com/pdfs/nahcolite.pdf Handbook of Mineralogy
- ^ a b c http://www.webmineral.com/data/Nahcolite.shtml Webmineral data
- ^ Richard V. Gaines, H. Catherine W. Skinner, Eugene E. Foord, Brian Mason, and Abraham Rosenzweig: Dana's new mineralogy, John Wiley & Sons, 1997
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