Analcime

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Analcime
Analcime, Aegirine, Natrolite-225835.jpg
Analcime with aegirine and natrolite from Mont Saint-Hilaire, Québec (size: 78 x 65 x 53 mm)
General
Category Zeolite
Formula
(repeating unit)
NaAlSi2O6·H2O
Strunz classification 09.GB.05
Crystal system Cubic; tetragonal, orthorhombic, or monoclinic, pseudocubic, with degree of ordering.
Identification
Color White, colorless, gray, pink, greenish, yellowish
Crystal habit Typically in crystals, usually trapezohedrons, also massive to granular.
Twinning Polysynthetic on [001], [110]
Cleavage Very poor [100]
Fracture Uneven to subconchoidal
Mohs scale hardness 5 - 5.5
Luster Vitreous
Streak White
Specific gravity 2.24 - 2.29
Optical properties Isotropic; anomalously biaxial (-)
Refractive index n = 1.479 - 1.493
Fusibility 3.5
Other characteristics Weakly piezoelectric; weakly electrostatic when rubbed or heated.
References [1]

Analcime or analcite (from the Greek analkimos - "weak") is a white, gray, or colorless tectosilicate mineral. Analcime consists of hydrated sodium aluminium silicate in cubic crystalline form. Its chemical formula is NaAlSi2O6·H2O. Minor amounts of potassium and calcium substitute for sodium. A silver-bearing synthetic variety also exists (Ag-analcite).

Analcime is usually classified as a zeolite mineral, but structurally and chemically it is more similar to the feldspathoids. Analcime occurs as a primary mineral in analcime basalt and other alkaline igneous rocks. It also occurs as cavity and vesicle fillings associated with prehnite, calcite, and zeolites.

Locations[edit]

Well known locations for sourcing analcime include Croft Quarry in Leicestershire, UK; the Cyclopean Islands east off Sicily and near Trentino in northern Italy; Victoria in Australia; Kerguelen Island in the Indian Ocean; in the Lake Superior copper district of Michigan, Bergen Hill, New Jersey, Golden, Colorado, and at Searles Lake, California in the United States; and at Cape Blomidon, Nova Scotia and Mont Saint-Hilaire, Quebec in Canada; and in Iceland.

See also[edit]

References[edit]

  1. ^ Handbook of Mineralogy, Mineral Data Publishing

External links[edit]