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blackdamp

Generally applied to carbon dioxide. Strictly speaking, a mixture of
nitrogen and carbon dioxide. The average blackdamp contains 10% to 15%
carbon dioxide and 85% to 90% nitrogen. It is formed by mine fires and the
explosion of combustible gases in mines, and hence forms a part of the
afterdamp. An atmosphere depleted of oxygen rather than containing an
excess of carbon dioxide. Being heavier than air, it is always found in a
layer along the floor of a mine. It extinguishes light and suffocates its
victims. Hence, it is sometimes known as chokedamp. See also:afterdamp;
damp. Fay; Korson

black diamond

a. A variety of crystalline carbon, related to diamond, but showing no
crystal form. Highly prized as an abrasive because of its hardness. Occurs
only in Brazil. Syn:carbonado
b. A term frequently applied to coal.
c. A black gem diamond.
d. Dense black hematite that takes a polish like metal.

black flux

A reducing flux composed of powdered carbon and alkali-metal carbonate.
Webster 3rd

black garnet

See:andradite

black gold

a. A slang American term referring to crude oil.
b. Syn:Maldonite
c. Placer gold coated with a black or dark-brown substance (such as a film
of manganese oxide) so that the yellow color is not visible until the
coating is removed. AGI

black granite

A commercial term for crystalline rock that when polished is dark gray to
black. It may be a diabase, diorite, or gabbro. AGI

black gunpowder

A mixture of potassium nitrate (saltpeter), sulfur, and charcoal in
varying proportions. A typical composition is 70% to 75% saltpeter, 10% to
14% sulfur, and 14% to 16% charcoal. It is designated according to grain
size: mealed; superfine grain (FFG); fine grain (FG); large or coarse
grain (LG); large grain for rifles (RLG); and mammoth.
Syn:black powder

black hematite

See:psilomelane

black iron

Malleable iron, untinned; distinguished from tinned or white iron.
Standard, 2

black iron ore

See:magnetite

blackjack

a. A thin stratum of coal interbedded with layers of slate; a slaty coal
with a high ash content. AGI
b. A syn. of sphalerite, esp. a dark variety. See also:sphalerite
AGI

black lead

a. An obsolete name for graphite, still used in naming lead pencils, which
are really made of graphite. Syn:plumbago
b. Graphite, in impure crystalline form. Pryor, 3
c. Used for coating patterns and the faces of cast-iron chilling molds.
Crispin

blacklead ore

An early name for the black variety of cerussite. Fay

black light

a. A prospector's and miner's term for ultraviolet light, used in
exploration and evaluation to detect mineral fluorescence. AGI
b. An instrument, usually portable, that produces ultraviolet light for
this purpose. See also:lamp

black liquor

The alkaline spent liquor from the digesters in the manufacture of sulfate
or soda wood pulp.

black liquor recovery furnaces

Smelting or recovery furnaces in which evaporated black liquor is burned
to a molten chemical smelt.

blacklung

See:anthracosis

black magnetic rouge

A polishing material consisting of 99% Fe3 O4 .
See also:black rouge

black manganese

a. See:hausmannite
b. A term applied to dark-colored manganese minerals; e.g., pyrolusite,
hausmannite, and psilomelane.

black metal

A black shale associated with coal measures. AGI

black mica

See:biotite