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Spinel:
Multiple Oxides (Magnesium aluminum oxide, in which magnesium can be partly or completely replaced by iron, zinc or manganese) MgAl2O4 AKA: Almandine spinel, Pleonast, Rubicelle, Ruby spinel |
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System: Isometric; usually in octahedrons; cubes and dodecahedrons rare; also granular, compact, disseminate. Appearance: Red, green, blue, brown, black; vitreous, dull; streak white. Physical Properties: Hardness: (7.5 - 8.0); Specific gravity: (3.6 - 4.0). Cleavage: none; fracture, conchoidal; brittle; transparent to opaque; sometimes fluorescent. Similar species: Magnetite is magnetic; chromite and zircon have higher gravity; and garnet does not crystallize in octahedral form. Occurrence: Spinel forms in plutonic and metamorphic rocks. It is associated with olivine and hornblende in gabbro of plutonic rocks, and can be found in hornfels and marbles of metamorphic rocks. The finest spinel comes from localities in Ceylon and Burma. In North America spinel can be found in Ontario, New York, New Jersey and California. Miscellaneous: Gem quality spinel was known for many years as a substitute for ruby and sapphire. Spinel occurs in many colors: red, pink, rose and yellow to orange spinel is called rubicelle; purple spinel is called almandine spinel, and blue or dark green to black spinel is called pleonast. Because spinel usually contained fewer flaws than ruby, it was frequently substituted for the rubies in the crowns of England and Russia. Spinels are faceted. The name is of uncertain origin, but is probably from the Latin spina, "thorn", in reference to its sharply pointed crystals. Conventional Wisdom: This mineral can be used to renew energy and to provide encouragement for further attempts at difficult tasks. It can also be used to enhance ones appearance, to increase the positive aspects of ones personality, and to assist in obtaining, maintaining and accepting victory with humility. The energy of spinel is the energy of beauty. It is known as the stone of immortality, bringing freshness to all endeavors and initiating rejuvenation to that which is beginning to degrade. Belongs to the Astrological Signs of Sagittarius and Aries. |