An isometric mineral, Ag3 AuTe2 ; metallic; steel gray to
iron black; massive; sp gr, 8.7 to 9.02; in gold-bearing telluride veins;
may be a significant source of gold and silver.
The negative logarithm (base 10) of the hydrogen-ion activity. It denotes
the degree of acidity or of basicity of a solution. At 25 degrees C, 7 is
the neutral value. Acidity increases with decreasing values below 7, and
basicity increases with increasing values above 7. ASM, 1
See:kaliophilite
A concordant intrusive in the crest of an anticline and trough of a
syncline; in cross section, it has the shape of a doubly convex lens. Adj:
phacolithic. See also:laccolith
An igneous rock having the grains of its essential minerals large enough
to be seen macroscopically. AGI
Said of the texture of an igneous rock in which the individual components
are distinguishable with the unaided eye, i.e., megascopically
crystalline. Also, said of a rock having such texture. CF:aphanitic
Syn:macromeritic; phanerocrystalline; phenocrystalline. AGI
See:phaneritic
That part of geologic time represented by rocks in which the evidence of
life is abundant, i.e. Cambrian and later time. CF:Cryptozoic
AGI
A crystal or mineral aggregate within which an earlier stage of
crystallization or growth is outlined by dust, tiny inclusions, or
bubbles; e.g., a trigonal scalenohedron of calcite coated with hematite
and overgrown with a clear calcite rhombohedron in crystallographic
continuity. Syn:ghost crystal
a. In seismic reflection prospecting, a line drawn on seismic sections so
that it is parallel to nearby dip segments thought to indicate structural
attitude. It is used where actual events are not continuous enough to be
used alone. AGI
b. Horizon on a reflection profile that is obtained by averaging the dips
of the reflections within a band, thus indicating the trend of the dip,
but not necessarily coinciding with an actual boundary plane.
Schieferdecker
A monoclinic mineral, CaHAsO4 .2H2 O ; white to gray; forms
silky fibers; occurs in the oxidized parts of arsenical deposits.
Syn:arsenic bloom
An isometric mineral, KFe4 (AsO4 )3 (OH)4
.6-7H2 O; crystallizes in cubes or tetrahedra with cubic cleavage;
rarely massive; occurs widely as an oxidation product of arsenical ores.
Syn:cube ore
a. The sum of all those portions of a material system that are identical
in chemical composition and physical state. CTD
b. A homogeneous, physically distinct portion of matter in a heterogeneous
system. AGI
c. An interval in the development of a given process; esp. a chapter in
the history of the igneous activity of a region, such as the volcanic
phase and major and minor intrusive phases. AGI
d. A lithologic facies, esp. on a small scale, such as a minor variety
within a dominant or normal facies, or a facies of short duration or local
occurrence; e.g., a marine phase or a fluviatile phase. AGI
An angle expressing phase or phase difference. Webster 3rd
Relay that protects an electrical system from faults occurring in any
phase of a three-phase system. Quite often a fault current will not be
large enough to trip the overcurrent relay, but will operate the
phase-balance mechanism. Coal Age, 3
The process of varying the point within the cycle at which anode
conduction is permitted to begin. Coal Age, 1
A machine for converting an alternating current into an alternating
current of a different number of phases and the same frequency.
Webster 3rd
A graph designed to show the boundaries of the fields of stability of the
various phases of a system. The coordinates are usually two or more of the
intensive variables temperature, pressure, and composition, but are not
restricted to these. Syn:equilibrium diagram
In solvent extraction or liquid-liquid extraction procedures, allowing the
mixture of aqueous liquor and organic solution phases to separate for
individual recovery and further treatment.
In solvent extraction technology, the rate of disengagement of phases
(aqueous and organic carrier).
The angle by which the amount of difference of phase between two
alternating-current magnitudes is expressed. Standard, 2