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Analcite

Analcite
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General
CategoryMineral
Chemical formulaNaAlSi2O6·H2O
Identification
Color Colorless to white
Crystal habit Typically in crystals, usually trpezohedrons, also massive to granular.
Crystal system Isometric; 4/m bar 3 2/m
CleavageAbsent
FractureUneven
Mohs Scale hardness 5 - 5.5
LusterVitreous
Refractive indexnα=1.479 - 1.493 nγ=1.480 - 1.494
Pleochroism .
Streakwhite
Specific gravity 2.27
Fusibility3.5
Solubility.
Other Characteristics.

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

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

Locations include the Cyclopean Islands and near Trentino, Italy; Victoria, Australia; Kerguelen Island in the Indian Ocean; in the Lake Superior copper district of Michigan, Bergen Hill, New Jersey, Golden, Colorado in the United States; and at Cape Blomidon, Nova Scotia and Mont St. Hilaire , Quebec; and in Iceland.

See also

References and external links



07-14-2008 23:18:10
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