Hanksite
(repeating unit)Na22K(SO4)9(CO3)2Cl IMA symbol Hks[1] Strunz classification 7.BD.30 Crystal system Hexagonal Crystal class Dipyramidal (6/m)
H–M symbol: (6/m) Space group P63/m Unit cell a = 10.465(21) Å
c = 21.191(43) Å; Z = 2 Identification Color Colorless to pale yellow, may be grayish green due to clay inclusions Crystal habit Occurs as short prismatic to tabular hexagonal crystals Cleavage Good on {0001} Fracture Uneven Tenacity Brittle Mohs scale hardness 3–3.5 Luster Vitreous to dull Streak White Diaphaneity Transparent to translucent Specific gravity 2.562 Optical properties Uniaxial (−) Refractive index nω = 1.481, nε = 1.461 Birefringence δ = 0.020 Ultraviolet fluorescence Pale yellow under LW UV Solubility Readily soluble in water References [2][3][4] 
H–M symbol: (6/m)
c = 21.191(43) Å; Z = 2
Hanksite is a sulfate mineral, distinguished as one of only a handful that contain both carbonate and sulfate ions (a sulfate carbonate). It has the chemical formula Na22K(SO4)9(CO3)2Cl.
Occurrence
It was first described in 1888 for an occurrence in Searles Lake, California, and named for American geologist Henry Garber Hanks.[3][4] Hanksite is normally found in crystal form as evaporite deposits. Hanksite crystals are large but not complex in structure. It is often found in Searles Lake, Soda Lake, Mono Lake, and in Death Valley. At its deposits in San Bernardino County, California hanksite is commonly found beneath the surface embedded in mud or in drill cores (Palache et al., 1960). It is associated with halite, borax, trona, and aphthitalite at the Searles Lake locality.[2] It is also associated with borax mining in the Soda Lake area. [citation needed]
Physical characteristics
Hanksite can be colorless, white, gray, green, or yellow, and is transparent or translucent. The mineral's hardness is approximately 3 to 3.5. The specific gravity is approximately 2.5 (slightly below average). It is salty to the taste and sometimes glows pale yellow in ultraviolet light. Typical growth habits are hexagonal prisms or tabular with pyramidal terminations. The streak of Hanksite is white. It can contain inclusions of clay that the crystal formed around while developing.
Similar minerals
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References
- ^ Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine. 85 (3): 291–320. Bibcode:2021MinM...85..291W. doi:10.1180/mgm.2021.43. S2CID 235729616.
- ^ a b Handbook of Mineralogy.
- ^ a b Mindat.org.
- ^ a b Webmineral data.
Bibliography
- Palache, P.; Berman H.; Frondel, C. (1960). "Dana's System of Mineralogy, Volume II: Halides, Nitrates, Borates, Carbonates, Sulfates, Phosphates, Arsenates, Tungstates, Molybdates, Etc. (Seventh Edition)" John Wiley and Sons, Inc., New York, pp. 628-629.
