Analcite Composition,
Crystallization & Structure

Composition. Hydrous sodium-aluminium metalisicat, Na-AlSi₂O₆H₂O = Silica 54.5, alumina 23.2, soda 14.4 water 8.2. Note similarity in composition to leucite, KAlSi₂O₆.

Crystallization. Isometric. Usually in trapesohedrons. Cubes with trapezohedral truncation also known.

Structure. Usually in crystals, also massive granular.

 Physical Properties. H. = 5-5.5. G. = 2.27. Vitreous luster. Colorless or white. Transparent to nearly opaque.

Test. Fusible at 3.5 becoming firs opaque and then a clear glass. Colours the flame yellow (sodium). Decomposed by hydrochloric acid with the separation of silica without the formation of a jelly. Gives water in C. T. Usually recognized by its crystals and its Vitreous luster.

Occurrence. Commonly a secondary mineral, formed by the action of hot circulating waters, and is to be found deposited in the cavities of igneous and especially volcanic rocks. Associated with calcite, and various zeolites and related minerals. Also times as an original constituted of igneous rocks, as in the analcite-basalts.

Fine crystals found at Bergen Hill, etc., New Jersey; in the lake Superior copper district; at Table Mountain, near Golden, Colorado; at Cape Blomidon, etc., nova Scotia; in the Cyclopean Islands near Sicily; in the lake superior copper districts; at Table Mountain, near Golden, Colorado; at Cape Blomidon, etc., Nova Scotia; in the Cyclopean Islands near Sicily; in the Val diffuse and on the Seizer Alpe, Trentino, Italy; from Victoria, Australia; Kerguelen Island in the Indian ocean.

Name. Derived from a Greek word meaning weak, in allusion to its weak electric power when heated or rubbles.