| baryto-calcite | <chemical> A mineral of a white or gray colour, occurring massive or crystallized. It is a compound of the carbonates of barium and calcium. Origin: Baryta + calcite. Source: Websters Dictionary (01 Mar 1998) |
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| calcite | <microscopy> A doubly refracting mineral used in the manufacture of polarizing prisms. It is uniaxial negative and in the trigonal diversion of the hexagonal system of crystals. Its indexes are epsilon =1.486, omega =1.658, its hardness is 3 on the Mohr scale and specific gravity 2.711. See: balsam, Canada. (05 Aug 1998) |