A small coal washer to deal with the 1/2- to 0-in (1.3- to 0-cm) range. It
works on the same basic principle as the Baum washer, but in view of the
small-size material a feldspar (sp gr, 2.6) bed is provided on the
perforated grid plates to prevent the bulk of the feed from passing
straight through the perforations. Stratification of the raw feed takes
place in the usual way. Nelson
See:sunstone
A washbox to clean small coal, in which the pulsating water is made to
pass through a layer of graded material, such as feldspar, situated on top
of the screen plate. See:jig
Said of a rock or other mineral aggregate containing feldspar.
Emery similar to spinel emery but contains in addition from 30% to 50%
plagioclase feldspar. Pure magnetite often is found in streaks within this
mass. AIME, 1
A graywacke characterized by abundant unstable materials; specif., a
sandstone containing generally less than 75% of quartz and chert and 15%
to 75% detrital clay matrix, and having feldspar grains (chiefly sodic
plagioclase, indicating a plutonic provenance) in greater abundance than
rock fragments (indicating a supracrustal provenance) (Pettijohn, 1954;
1957). CF:lithic graywacke
A feldspar-rich sandstone; specif., a sandstone intermediate in
composition between an arkosic sandstone and a quartz sandstone,
containing 10% to 25% feldspar and less than 20% matrix material of clay,
sericite, and chlorite. See also:arkose
See:feldspathoid
The introduction of feldspar into a rock, or the replacement of other
rock-forming minerals by feldspar. Material for the feldspar may come from
the country rock or be introduced by magmatic or other solutions.
a. A group of comparatively rare rock-forming minerals consisting of
aluminosilicates of sodium, potassium, or calcium and having too little
silica to form feldspar. Feldspathoids are chemically related to the
feldspars, but differ from them in crystal form and physical properties;
they take the places of feldspars in igneous rocks that are undersaturated
with respect to silica or that contain more alkalies and aluminum than can
be accommodated in the feldspars. Feldspathoids may be found in the same
rock with feldspars but never with quartz or in the presence of free
magmatic silica. See also:foid; lenad. AGI
b. A mineral of the feldspathoid group, including leucite, nepheline,
sodalite, nosean, hauyne, lazurite, cancrinite, and melilite.
Syn:feldspathide
A rock having a fine granular structure, and composed chiefly of feldspar
and quartz. Gordon
A constituent of portland cement clinker. Also spelled felith.
See:belite; larnite.
a. One of the many names for lead ore.
b. The finer pieces of ore that pass through the riddle in sorting.
A group of minerals comprising the feldspars and feldspathoids.
CF:feldspathoid
See:block field
A mnemonic adj. derived from (fe) for feldspar, (l) for lenad or
feldspathoid, and (s) for silica, and applied to light-colored rocks
containing an abundance of one or all of these constituents. Also applied
to the minerals themselves, the chief felsic minerals being quartz,
feldspar, feldspathoid, and muscovite. Syn:acidic; silicic.
CF:mafic
A general term for any light-colored, fine-grained or aphanitic extrusive
or hypabyssal rock, with or without phenocrysts, and composed chiefly of
quartz and feldspar; a rock characterized by felsitic texture.
Syn:felstone; aphanite. CF:felsophyre
A textural term ordinarily applied to dense, light-colored igneous rocks
composed of crystals that are too small to be readily distinguished with
the unaided eye; microcrystalline. It may also be used as a microscopic
term for the groundmass of porphyritic rocks that are too fine-grained for
the mineral constituents to be determined with the microscope;
cryptocrystalline.
An informal term applied to any light-colored igneous rock in which the
mineral grains are too small to be distinguished by the unaided eye.
CF:felsite
An orthorhombic(?) mineral, Al4 (SO4 )(OH)11 .5H (sub
2) O ; massive; soft; snow white; associated with marcasite, stibnite, and
barite at Felsoebanya, Romania. Also spelled felsoebanyite.
CF:basaluminite
A general term for any porphyritic felsite. Syn:aphanophyre
CF:vitrophyre; granophyre. AGI