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Actinolite:
Inosilicates (Hydrous calcium magnesium iron silicate; amphibole group) Ca2(Mg,Fe)5SiO22(OH)2 AKA: Nephrite |
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System: Monoclinic; usually long prismatic with diamond-shaped cross section; also bladed, acicular, columnar, divergent. Appearance: Bright to dark green, grayish green, black; vitreous, pearly, silky; streak colorless. Physical properties: Hardness:(5 - 6); Specific gravity: (3.0 - 3.5); Cleavage: perfect cleave parallel to the vertical prism; fracture, splintery, uneven; transparent to translucent. Similar species: Wollastonite is usually fluorescent; tourmaline has no cleavage; and epidote lacks the cleavage angle of actinolite. Occurrence: Actinolite results principally from metamorphic processes. It is associated with albite, chlorite and epidote in greenstone of regional metamorphic rocks; with albite and muscovite in hornfels of contact metamorphic rocks; and barite and anhydrite in massive hydrothermal replacement deposits. Beautiful green blades of actinolite up to 12.5 cm (5") in length occur in talc in Vermont. Deep-green actinolite is common among the bodies of serpentinite in California. Nephrite, which is usually a chemical mixture of actinolite and tremolite, has been found in substantial amounts in British Columbia, Alaska, California and Wyoming. Miscellaneous: Actinolite is used as an ornamental stone in jewelry and is often confused with jadeite, which is more valuable. The name is from the Greek aktinos, "ray", in reference to the common radiate habit of prismatic crystals. Conventional Wisdom:A power stone for artisans. For those who are doing artistic, creative projects: Enables one to stay focused and to handle several projects at one once without becoming scattered or sidetracked. Helps one build an empire in the area of art and creativity, or to master one's creative abilities. Belongs to the Astrological Sign of Scorpio. |