Paulingite | |
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General | |
Category | Tectosilicate minerals, zeolite group |
Formula | (K,Na,Ca) 3–4(Si,Al) 21O 42•17-22H 2O |
IMA symbol | Pau[1] |
Strunz classification | 9.GC.35 |
Crystal system | Cubic |
Crystal class | Hexoctahedral (m3m) H-M symbol: (4/m 3 2/m) |
Space group | Im3m |
Identification | |
Color | Colorless, light yellow, orange, red |
Crystal habit | Typically as euhedral crystals |
Cleavage | None |
Fracture | Conchoidal |
Mohs scale hardness | 5 |
Luster | Vitreous to adamantine |
Diaphaneity | Transparent |
Specific gravity | 2.085 – 2.24 |
Refractive index | n = 1.472–1.484 |
Ultraviolet fluorescence | None |
References | [2][3][4][5] |
Paulingite or paulingite-K is a rare zeolite mineral that is found in vesicles in the basaltic rocks from the Columbia River near Rock Island Dam, Washington.
Paulingite was named for Linus Carl Pauling (1901–1994), professor of chemistry, California Institute of Technology and accepted by the International Mineralogical Association in 1960.[4]
The early formation in the crystallization sequence and the high water content suggest that paulingite forms from relatively dilute pore fluids. They have a large unit cell of 3.51 nanometers and an isometric crystal system. This is the largest known inorganic unit cell apart from protein structures.[citation needed] Paulingite's characteristic structure can be observed while the remaining water content decomposes. A single crystal X-ray refinement of this chemically different sample material derived three main cation positions, which are inside a so-called paulingite or calcium (Ca), between 8-rings of neighbouring barium (Ba), and in the centre of the non-planar 8-rings of the -cage potassium (K).
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