Riebeckite: Inosilicates (Basic silicate of sodium and iron; amphibole group) Na2Fe32+Fe23+Si8O22(OH)2 AKA: Crocidolite IMAGES

System: Monoclinic; usually as long prismatic crystals showing a diamond-shaped cross section; also fibrous, bladed, acicular, columnar, radiating. Appearance: Dark blue to black; vitreous, silky in fibrous variety (crocidolite); streak white to blue-gray. Physical Properties: Hardness: (5.0 - 6.0); Specific gravity: (3.0 - 3.4). Cleavage: perfect, two directions in the shape of a diamond; fracture, uneven, splintery; translucent to nearly opaque. Similar species: Tourmaline lacks the good cleavage of riebeckite, and glaucophane can be distinguished, but not easily, from riebeckite by its generally lighter color. Occurrence: Riebeckite develops in igneous and metamorphic rocks. The dark-blue to black riebeckite that occurs as prismatic crystals develops in rhyolite of volcanic rocks and in granite pegmatities. The fibrous variety - crocidolite - is metamorphic in origin and develops along with almandine, quartz and albite in blue schist of regional metamorphic rocks. Black prismatic crystals come from Massachusetts and California. Crocidolite occurs in many places along the Coast Ranges of N. California and S.W. Oregon. Miscellaneous: Riebeckite is named in honor of Emil Riebeck (d. 1885), German explorer and mineralogist. Conventional Wisdom: This mineral can be used to encourage alteration in situations which inhibit ones growth. It can be used to bring one friendship and to facilitate cheerfulness. The energy of riebeckite can assist in providing guidance and insight to the solution of puzzling situations, encouraging the problem-solving capabilities inherent in the user. Belongs to the Astrological Sign of Libra.

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