The load at which a test piece breaks, divided by its original area.
See also:tensile strength
Said of an igneous rock having a silica content lower than that of a basic
rock. Percentage limitations are arbitrary; the upper limit was originally
set at 44%. The term is frequently used interchangeably with ultramafic.
Although most ultrabasic rocks are also ultramafic, there are some
exceptions; e.g., monomineralic rocks composed of pyroxenes are ultramafic
but are not ultrabasic because of their high silica content. A
monomineralic rock composed of anorthite would be considered ultrabasic
(SiO2 = 43.2%) but not ultramafic. Ultrabasic is one subdivision of
a widely used system for classifying igneous rocks on the basis of silica
content; the other subdivisions are acidic, basic, and intermediate.
CF:ultramafic; silicic. AGI
A germanium-bearing variety of diaphorite from Freiberg, Saxony, Germany.
A recently developed process for use in fine-particle flotation. The
underlying principle is the use of a finely ground (minus 325-mesh)
auxiliary mineral as a carrier for the fine particles to be floated. The
fine particles form a slime coating on the carrier mineral; the carrier
mineral is then floated, and the fines are piggybacked into the froth.
Fuerstenau
Said of an igneous rock composed chiefly of mafic minerals, e.g.,
monomineralic rocks composed of hypersthene, augite, or olivine.
CF:hypermelanic; ultrabasic. AGI
Collective name for igneous rocks containing 90% or more mafic minerals;
includes picrites, peridotites, and pyroxenites.
A name for synthetic lazurite; extended to related compounds. Also applied
to the durable brilliant blue pigment made from its powder.
Syn:lapis lazuli
A lemon-yellow pigment consisting of barium chromate. Fay
Metamorphic processes at the extreme upper range of temperatures and
pressures, at which partial to complete fusion of the affected rocks takes
place and magma is produced. The term was originated by Holmquist in 1909.
AGI
A microscope in which a strong beam of light (Tyndall beam) is viewed at
right angles. Individual soluble particles too small to be seen under a
normal microscope then appear as bright spots against a dark background.
Ultramicroscopy operates below 0.25 mu m. Pryor, 3
An ultracrushed variety of mylonite, in which primary structures and
porphyroclasts have been obliterated so that the rock becomes homogeneous
and dense, with little if any parallel structure. CF:protomylonite;
pseudotachylyte. Syn:flinty crush rock
The supposedly ultrabasic layer of the Earth below the sima, immediately
below the Mohorovicic discontinuity. AGI
A vibration drilling technique that can be used in drilling, cutting, and
shaping of hard materials. In this method, ultrasonic vibrations are
generated by the compression and extension of a core of electrostrictive
or magnetostrictive material in a rapidly alternating electric or magnetic
field. The most easily assembled is a magnetostrictive transducer, and the
most common magnetostrictive materials, which change in dimension when
magnetized, are nickel and vanadium permandur. Min. Miner. Eng., 1
A nondestructive method of testing, based upon the fact that ultrasonic
waves are reflected and refracted at the boundaries of a solid medium,
from which it is possible to obtain the echoes of a wave transmitted from
the surface of a test piece. In addition to being reflected from the
boundary of the specimen at which they are directed, the waves are also
reflected back by any flaws that lie in the path of the wave.
Syn:ultrasonic testing
Tests in which high-frequency vibrations (inaudible to a human ear) are
used to assist in determining wall thicknesses, pulp densities, etc.
Pryor, 3
A modification of the use of ultrasonic waves for the detection of
internal flaws in metals. By using a persistent screen cathode ray tube
and causing the echoes to brighten the trace instead of deflecting it, an
ultrasonic image is produced that can be examined and interpreted like a
radiograph. Osborne
a. Of radiation, beyond the visible spectrum at its violet end; having a
wavelength shorter than those of visible light and longer than those of
X-rays. Webster 3rd
b. Relating to, producing, or employing ultraviolet radiation.
CF:visible light
Electromagnetic waves in the wavelength between visible light rays and
X-rays. Ultraviolet light furnishes a quick method of finding and
identifying certain metals. Nelson
Alkylated monosodium benzene sulfonate, a wetting agent. Pryor, 3
See:ulvoespinel