A crystalline aggregate composed of closely packed fibers.
Thin strands of anthraxylon having the appearance of threads in thin
sections.
Translucent calcite composed of fibrous crystals, which, like fibrous
gypsum, with which it is often confused, causes a silky sheen. When cut
cabochon, it produces a girasol or chatoyant effect, but not a true
cat's-eye. Also like fibrous gypsum, it is called "satin spar" but less
correctly.
See:satin spar
a. Peat composed of the fibrous remains of plants. It is fibrous, spongy,
moderately tough, and nonplastic. It does not shrink much on drying. Also
called woody peat. See also:pseudofibrous peat; amorphous peat.
Tomkeieff
b. Firm, moderately tough peat in which plant structures are only slightly
altered by decay. It shrinks little on drying. Francis, 1
a. If the crystals in a mineral aggregate are greatly elongated and have a
relatively small cross section, the structure or texture is fibrous. The
fibers may be parallel, as in crocidolite and sometimes in gypsum and
cerussite. When the fibers are very fine, they may impart a silky luster
to the aggregate, as in crocidolite and satin-spar gypsum. There is also a
feltlike type. Fibrous crystals may radiate from a center, producing
asteriated or starlike groups, either coarse or fine, as frequently
observed in pyrolusite, wavellite, natrolite, and tourmaline, and
sometimes in stibnite and other minerals. Also called fibrous texture.
CMD
b. In forgings, a structure revealed as laminations, not necessarily
detrimental, on an etched section or as a ropy appearance on a fracture,
not to be confused with the silky or ductile fracture of a clean metal.
c. In wrought iron, a structure consisting of slag fibers embedded in
ferrite.
d. In rolled-steel plate stock, a uniform, fine-grained structure on a
fractured surface, free of laminations or shale-type discontinuities. As
contrasted with definition b., it is virtually synomous with silky or
ductile fracture. ASM, 1
In mineral deposits, a pattern of finely acicular, rodlike crystals, e.g.,
in chrysotile and amphibole asbestos. AGI
A fibrous variety of ozocerite, a natural paraffin wax.
See also:ozocerite
A monoclinic mineral, dimethyl-isopropyl-perhydropenanthrene, C19 H
34 ; translucent white; in fossil wood or conifers.
A measure of confidence in precision of a set of sample data. For a given
numerical value of fiducial interval, the number of samples required from
a given deposit to give an accurate measure of its value can be
determined. Lewis
In photogrammetry, an index or point used as a basis of reference; one of
usually four index marks connected with a camera lens (as on the metal
frame that encloses the negative) that form an image on the negative or
print such that lines drawn between opposing points intersect at and
thereby define the principal point of the photograph.
Syn:collimating mark
A time marked on a record to correspond to some arbitrary time. Such marks
may aid in synchronizing different records or may indicate a reference,
such as a datum plane. AGI
a. A region or area that possesses or is characterized by a particular
mineral resource; e.g., goldfield, coalfield. AGI
b. A broad term for the area, away from the laboratory and esp. outdoors,
in which a geologist makes observations and collects data, rock and
mineral samples, and fossils. AGI
c. That space in which an effect, e.g., gravity or magnetism, occurs and
is measurable. It is characterized by continuity; i.e., there is a value
associated with every location within the space. AGI
d. A section of land containing, yielding, or worked for a natural
resource; e.g., a coalfield, an oilfield, or a diamond field. A large
tract or area, as large as many square miles, containing valuable
minerals. See also:coalfield
e. The immediate locality and surroundings of a mine explosion.
f. A colliery, or firm of colliery proprietors.
The quantity of water held by soil or rock against the pull of gravity. It
is sometimes limited to a certain drainage period, thereby distinguishing
it from specific retention, which is not limited by time.
Syn:field-moisture capacity; normal moisture capacity. AGI
A classification of rocks made in the field. It is based on features
distinguishable in hand specimens by using a hand lens, a knife, an acid
bottle, etc. The classification may be refined or modified by subsequent
examination with a microscope or other techniques that are generally used
in a laboratory. Stokes
Tests carried out under site conditions to determine the best combination
of (1) type of compaction equipment; (2) thickness of loose soil layer;
(3) number of passes; and (4) moisture content (where variation is
possible) in order to achieve the highest possible soil densities.
Nelson
Geology as practiced by direct observation in the field; original, primary
reconnaissance; field work. AGI
In reference to experimental-mine tests, the investigation made at a mine
when a large sample is taken for testing at the experimental mine; this
investigation includes the taking of road dust, rib dust, mine air, and
standard coal samples, and the noting of conditions affecting the safety
of the mine. Rice, 2
A zinciferous variety of tetrahedrite. CF:goldfieldite
Person who analyzes mine water for acid, copper, and iron content by
removing samples of water that flow to and from the precipitation drum,
and who performs routine chemical tests. DOT
See:field capacity