calcareous sandstone

a. A sandstone cemented with calcite. AGI
b. A sandstone containing appreciable calcium carbonate, but in which
clastic quartz is present in excess of 50%. CF:calcarenite

calcareous sinter

See:travertine

calcareous spar

Coarsely crystalline calcium carbonate. See also:calcite

calcareous tufa

See:tufa

calcarinate

Adj. Designates the calcium carbonate cement of a sedimentary rock.
AGI

calc-dolomite

Rock consisting of both calcite and dolomite crystals. AGI

calce

Native calcium oxide, CaO, found on Mount Vesuvius, Italy. It formed from
limestone enveloped in lava and altered by the heat of the lava.
Hess

calcedony

See:chalcedony

calc-flinta

A fine-grained calc-silicate rock of flinty appearance formed by thermal
metamorphism of a calcareous mudstone, possibly with some accompanying
pneumatolytic action. See also:calc-silicate hornfels

calcian

See:calcic

calciborite

Calcium borate, CaB₂ O₄ , monoclinic. White radial
aggregates in drill cores from limestone skarn, from the Ural Mountains.
Named from the composition. See also:frolovite

calcic

Said of minerals and igneous rocks containing a relatively high proportion
of calcium; the proportion required to warrant use of the term depends on
circumstances. Said of a series of igneous rocks in which the weight
percentage of silica is greater than 61 when the weight percentages of CaO
and of K₂ O + Na₂ O are equal. Syn:calcian

calciclase

See:anorthite

calcinable

Capable of being calcined or reduced to a friable state by the action of
fire. Fay

calcination

a. The heating of a substance to its temperature of dissociation; e.g., of
limestone to CaO and CO₂ or of gypsum to lose its water of
crystallization. AGI
b. Heating ores, concentrates, precipitates, or residues to decompose
carbonates, hydrates, or other compounds. CF:roasting
ASM, 1; Newton, 1
c. Heating metals at high temperatures to convert them into their oxides.
Nelson

calcine

a. Ore or concentrate after treatment by calcination or roasting and ready
for smelting. CTD
b. By heating, to expel volatile matter as carbon dioxide, water, or
sulfur, with or without oxidation; to roast; to burn (said of limestone in
making lime). Fay

calcined gypsum

Gypsum partially dehydrated by means of heat, having the approximate
chemical formula, CaSO₄ .«H₂ O .

calciner

See:calcining furnace

calcining

a. Roasting of ore in oxidizing atmosphere, usually to expel sulfur or
carbon dioxide. If sulfur removal is carried to practical completion, the
operation is termed sweet roasting; if CO₂ is virtually removed,
dead roasting. Pryor, 3
b. Reducing to powder by heating. Mersereau, 2

calcining furnace

A furnace or kiln in which ores or metallurgical products are calcined.
Syn:calciner

calcioborite

An orthorhombic mineral, CaB₂ O₄ ; in white radial
aggregates in drill cores from limestone skarn in the Urals, Russia.