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Andradite:
Neosilicates (Calcium iron silicate) Ca3Fe3+2Si3O12 AKA: Demantoid, Garnet, Melanite, Topazolite |
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System: Isometric; crystals very common as dodecahedrons and trapezohedrons; also granular, lamellar, compact, disseminated. Appearance: Wine red; greenish (variety, demantoid), yellow (variety, topazolite), brown, black (variety, melanite); Vitreous; streak, colorless. Physical properties: Hardness: (6.5 - 7.5); Specific gravity; (3.87) varies with composition; Cleavage: None; parting sometimes distinct in six directions; fracture, conchoidal, uneven; brittle; Usually opaque but sometimes transparent with adamantine luster. White streak. Similar species: Apatite is softer than any of the garnets; zircon has a higher gravity and often fluoresces; tourmaline has lower gravity. Occurrence: Some garnets are of igneous origin, but most of them are products of metamorphism. Andradite occurs with albite and biotite in granite pegmatites; with orthoclase, calcite and wollastonite in carbonatites; with calcite and hedenbergite in hornfels of contact metamorphic rocks; and with magnetite and hedenbergite in skarn of hydrothermal metamorphic rocks. Brilliant black crystals (melanite) have been found in New Jersey and California; dark olive-green crystals up to 5 cm (2") across have come from Pennsylvania, demantoid has also been found in California; Topazolite is found in Valle della Gave, Genoa, and Val d'Ala, Turin (Italy); and reddish-black crystals at Franklin, New Jersey (USA). Miscellaneous: Andradite is named after J.B. de Andrada e Silva (1763 - 1838), Brazilian geologist. The different garnets are used industrially as abrasive materials. Demantois variety is highly regarded as a gemstone. Conventional Wisdom: This mineral works mainly to stabilize and enhance the "male" qualities; hence, providing strength, stamina, courage, etc. It is an excellent conductor and can be used to assist in the alignment of the magnetic fields of the body. Andradite also enhances the attractive aspects in relationships, attracting to one not that which is necessarily wanted, but bringing into ones life that which is essential for ones development. Belongs to the Astrological Sign of Aries. |