Nahcolite
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| Nahcolite | |
|---|---|
| General | |
| Category | Mineral |
| Chemical formula | NaHCO3 |
| Strunz classification | 05.AA.15 |
| Dana classification | 13.01.01.01 |
| Identification | |
| 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]
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]
[edit] 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
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