See:tennantite; tetrahedrite.
See:specularite
a. Pig iron or cast iron in which nearly all the carbon not included in
pearlite is present as graphitic carbon. See also:mottled iron;
white iron. CTD
b. Iron that exhibits a gray fracture surface because fracture occurs
along the graphite plates (flakes); it is the result of stable
solidification. McGraw-Hill, 1
A thorium phosphate containing a little lead, calcium, and minor uranium
and rare earths; gives an X-ray pattern like that of rhabdophane, and when
heated above 850 degrees C, a monazite-type pattern.
Am. Mineral., 1
Method of assessing the coking property of coal; 20 g is heated in a
silica tube to 600 degrees C and the residual product is compared with a
standard series ranging from noncoking (type A) to highly coking (G), all
of which have the same volume as the original. Cokes that expand (swell)
on coking receive a subscript indicating the degree of swelling.
Pryor, 3
See:manganite; pyrolusite.
An old rock name that has been variously defined but is now generally
applied to a dark gray, firmly indurated, coarse-grained sandstone that
consists of poorly sorted, angular to subangular grains of quartz and
feldspar, with a variety of dark rock and mineral fragments embedded in a
compact clayey matrix having the general composition of slate and
containing an abundance of very fine-grained illite, sericite, and
chloritic minerals. Graywacke is abundant within the sedimentary section,
esp. in the older strata, usually occurring as thick, extensive bodies
with sole marks of various kinds and exhibiting massive or obscure
stratification in the thicker units but marked graded bedding in the
thinner layers. It generally reflects an environment in which erosion,
transportation, deposition, and burial were so rapid that complete
chemical weathering did not occur, as in an orogenic belt where sediments
derived from recently elevated source areas were poured into a
geosyncline. Graywackes are typically interbedded with marine shales or
slates, and associated with submarine lava flows and bedded cherts; they
are generally of marine origin and are believed to have been deposited by
submarine turbidity currents. CF:arkose; subgraywacke. Also spelled:
greywacke; grauwacke. AGI
One of numerous fragments or blocks of sandstone and conglomerate,
covering large tracts in Dorsetshire and Wiltshire, England, supposed to
be remnants of decomposed Tertiary strata. Also called druidical stone;
sarsen stone; saracen stone. Syn:sarsen stone
a. A semisolid form of lubricant, composed of emulsified mineral oil and
soda or lime soap. Additives may be incorporated for special purposes, for
example, colloidal graphite.
b. This term should be applied only to fatty or oily matter of animal
origin, but mixtures of mineral oil with lime and soda soaps constitute
well-known lubricating greases.
c. Term used in the flotation process.
d. As used in engineering for lubrication or protection of metal surfaces,
grease is an emulsified oil or saturated fatty acid combined with a
suitable alkaline base to form a soap. Pryor, 3
e. Thick oil. Nichols, 1
f. A solid or semisolid mixture of oil with soap or other fillers.
Nichols, 1
A process in which separation is based on selective adhesion of some
grains (diamonds) to quasi-solid grease with adhesion of other grains to
water. Gaudin, 1
a. A person who oils or greases the mine cars.
b. An automatic apparatus that greases the axles of skips as they pass.
A name for steatite or soapstone.
An apparatus for concentrating minerals, such as diamonds, which adhere to
grease. It usually is a shaking table coated with grease or wax over which
an aqueous pulp is flowed.
An electrically driven service vehicle to transport greases and oil for
servicing the underground mine machinery. It may include a compressor, air
storage tank, and fittings to place lubricant at the proper points in the
mining machinery.
Applied to the luster of minerals. Having the luster of oily glass, as
elaeolite. Fay
Scot. See:creeshy
Some minerals or rocks are greasy or soapy to the touch, e.g., talc,
graphite, steatite, or soapstone.
See:fine gold
As if covered with a thin film of oil or grease, e.g., nepheline, some
diamond crystals, and some varieties of serpentine.
See:milky quartz
A pear-shaped vessel that resembles the Bessemer converter. It has been
largely supplanted by the cylindrical (Peirce-Smith) type converter.
Newton, 1