Sanidine


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sanidine

[′san·ə‚dēn]
(mineralogy)
KAlSi3O8 An alkali feldspar mineral occurring in clear, glassy crystals embedded in unaltered acid volcanic rocks; a high-temperature, disordered form. Also known as glassy feldspar; ice spar; rhyacolite.

Sanidine

 

a rock-forming, monoclinic variety of feldspar; it is a solid solution of KAlSi3O8 and NaAlSi3O8, with the content of the potassium component ranging from 100 to 37 percent and a disordered distribution of Al and Si in the structure. At less than 37 percent KAlSi3O8, the structure becomes triclinic (high-temperature albite). In solid solution, sanidine contains up to 5–10 percent CaAl2Si2O8. Sanidine is one of the chief minerals of young extrusive and hypabyssal acid rocks (seeFELDSPAR).

References in periodicals archive ?
One variety of lamproite, rich in enstatite, sanidine and phlogopite, is referred to as Cancalite or Cancarixite due to its occurrence at the Volcano of Cancarix (Parga-Pondal, 1935; Fuster et al., 1967), though this term is not generally accepted.
The hyalite-bearing layer is composed of 3-50 mm rhyolite rock fragments mixed with 1-4 mm dipyramidal fe-quartz and limpid sanidine phenocrysts in a weakly welded, porous, siliceous, tuffaceous matrix.
After the analyses, the soil minerals found were: quartz, calcite, sanidine, albite, nontronite, muscovite, montmorillonite, hematite, faujasite, dolomite, microcline, anorthite, anorthoclase, clinochlore and epidote.
Sintered sanidine glass-ceramics from industrial wastes, Journal of the European Ceramic Society 26: 3335-3341.
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tuff containing sanidine (Wilf et al., 2003, 2005).
Albite, sanidine, Sb and ZnS were used as standards.