a. An atomic vacancy. Van Vlack
b. A point defect in a crystal structure where an atom is missing from a
correct site. Syn:vacancy
c. A defect in anionic crystal in which a single ion is removed from its
interior lattice site and relocated in a lattice site at the surface of
the crystal.
d. A defect in anionic crystal consisting of the smallest number of
positive-ion vacancies and negative-ion vacancies that leave the crystal
electrically neutral.
See:cutter plow
A tetragonal mineral, (Fe,Ni)3 P ; highly magnetic; contains small
amounts of cobalt and traces of copper and tarnishes to brass yellow or
brown. Schreibersite occurs in tables or plates as oriented inclusions in
iron meteorites. Syn:rhabdite
A triclinic mineral, NaCa3 (UO2 )(CO3 )3 (SO
4 )F.10H2 O; radioactive; soft; greenish-yellow color and
fluorescence; an alteration product of uraninite; a source of uranium.
Also spelled schroeckingerite. Syn:dakeite
An opaline variety of allophane rich in aluminum. Material at the type
locality is a mixture of glassy hyalophane and earthy variscite.
A name for interlayered Ni-rich vermiculites and chlorites.
A hexagonal mineral, Hg3 (SO4 )O2 ; yellow.
An orthorhombic mineral, PbCu(Nd,Gd,Sm,Y)(CO3 )3 (OH).1.5H
2 O ; light blue.
A monoclinic mineral, PbHAsO4 ; forms colorless thin crystalline
plates; resembles selenite; at Tsumeb, Namibia.
The original type of water elutriator; it has since been improved.
Dodd
This states that the ion that causes a soluble to coagulate is opposite in
sign to the electric charge of the colloidal particle; further, the
coagulating power increases with the valency of the ion. Pryor, 3
A mine subsidence theory that distinguishes between the manner of fracture
of shale and sandstone, holding that the former rock breaks along vertical
lines irrespective of the angle of dip, and that the latter has a vertical
fracture over a rise face and a fracture at right angles to the bed over a
dip face. The theory predicts vertical lines of break in either rock for a
level seam, and is, indeed, a compromise between the vertical theory and
that of the normal. Briggs
Integral plot in graphic representation of sizing analysis.
Pryor, 3
See:shungite
A mercurian variety of tetrahedrite. Also spelled schwazite.
A synthetic corundum colored by vanadium oxide to resemble true
alexandrite in some of its optical characters.
A synthetic beryl glass colored by chromic oxide to resemble true emerald
in color.
A very small light flash excited in certain natural or synthetic crystals
by radioactive rays or particles; the basic phenomenon of the
scintillation counter in which the photoelectric effect of the
scintillation flashes is amplified and measured to give a measure of
intensity of radioactivity. AGI
A sensitive instrument for the location of radioactive ore, such as
uranium, radium, and thorium. It uses a transparent crystal that gives off
a minute flash of light when struck by a gamma ray, and a photomultiplier
tube that produces an electrical impulse when the light from the crystal
strikes it. The scintillation counter has advantages over the Geiger
counter as it is more sensitive, more compact, and can distinguish between
types of radiation. The instrument responds to gamma rays emitted from the
minerals mentioned and charts their intensity. It is used in aerial
geophysical prospecting and the resulting maps are used as a guide for a
more detailed ground investigation. See also:coal-sensing probe
Nelson
An electronic logging device consisting of a scintillation-type gamma-ray
detecting unit built into a container small enough to be lowered into a
borehole. Long