A monoclinic mineral, Ag16 As2 S11 , having copper as
an apparent necessary minor component; forms pseudorhombohedral tabular
crystals or may be massive; metallic black; brittle; in low-to
moderate-temperature silver and base-metal ores.
A dense spherical calcareous concretion, usually white or light-colored,
consisting of occasional layers of conchiolin and predominant nacrous
layers of aragonite (or rarely calcite); deposited concentrically about a
foreign particle within or beneath the mantle of various marine and
freshwater mollusks; occurs either free from or attached to the shell.
Potassium carbonate, K2 CO3 ; esp., an impure product
obtained by partial purification of potash from wood ashes.
Webster 3rd
The lamellar mixture of ferrite and cementite in the microstructure of
slowly cooled iron-carbon base alloys occurring normally as a principal
constituent of both steel and cast iron. Webster 3rd
a. In general, pearlite iron is gray cast iron consisting of graphite in a
matrix of pearlite; i.e., without free ferrite. CTD
b. In particular, pearlite iron is a German proprietary name denoting an
iron of low silicon content, which is caused to solidify gray by the use
of heated molds. CTD
See:margarite
See:cacholong
A variety of opal. Syn:fiorite
Fay
Dolomite occurring in rhombohedrons having a pearly luster.
Syn:ankerite; bitter spar. See also:dolomite
See:perlite
Applied to minerals having a luster like a pearl; e.g., talc, brucite, and
stilbite. See also:nacre
See:pisolite
There are two types of peat, low moor (Flachmoor) and high moor (Hochmoor)
peat. Low moor peat is the most common starting material in coal genesis.
It therefore constitutes a caustobiolith of low diagenetic degree. Peat is
formed in marshes and swamps from the dead, and partly decomposed remains
of the marsh vegetation. Stagnant ground water is necessary for peat
formation to protect the residual plant material from decay. Peat has a
yellowish brown to brownish black color, is generally of the fibrous
consistency, and can be either plastic or friable; in its natural state it
can be cut; further, it has a very high moisture content (above 75%,
generally above 90%). It can be distinguished from brown coal by the fact
that the greater part of its moisture content can be squeezed out by
pressure (e.g., in the hand). Peat also contains more plant material in a
reasonably good state of preservation than brown coal. Individual plant
elements, such as roots, stems, leaves, and seeds, can commonly be seen in
it with the unaided eye. Failing that, treatment of peat with dilute
alkali will make visible many of these plant tissues. Further, peat is
richer in cellulose than brown coal (reaction with Fehling's solution).
Unlike brown coal, peat still contains cellulose, protected by lignin or
cutin, which gives a reaction with chlorzinc iodide. Correspondingly, peat
shows under the microscope tissues that have not undergone either
lignification, suberinization, or cutinization; this is not the case in
brown coal. The reflectance of peat is low (about 0.3%). Microscopic
examination is best undertaken with transmitted light. IHCP
An accumulation of peat. Fay
A method enabling a road to be built across peat deposits. Hard filling is
first dumped over the route to a height equal to the ascertained depth of
the peat, into which blasting charges are inserted. By the action of
blasting, the peat is displaced outwards and the hard fillings sink into
place and can then be consolidated. Hammond
A bog containing peat; an accumulation of peat. Webster 3rd
See:dopplerite
A pit or quag formed by digging out peat. Standard, 2
A machine for grinding and briquetting peat. Webster 3rd
A digger or seller of peat. Webster 3rd
Any moss from which peat has formed or may form. Webster 3rd