A prefix meaning strange or foreign.
A crystal that has grown during metamorphism without the development of
its characteristic faces. CF:idioblast
Applied to a texture of metamorphic rocks in which the constituent mineral
grains lack proper crystal faces.
A crystal in an igneous rock that is foreign to the body of rock in which
it occurs. CF:xenolith
A little-used syn. of epigenetic. AGI
A silicate of aluminum, related to fibrolite. Fay
A foreign inclusion in an igneous rock. CF:autolith; xenocryst.
Syn:inclusion; exogenous inclusion; accidental inclusion. AGI
a. Said of the holocrystalline texture of an igneous or metamorphic rock,
characterized by crystals not bounded by their own faces but with their
forms impressed upon them by adjacent mineral grains. Also said of a rock
with such a texture. AGI
b. (Syn:anhedral
anidiomorphic; xenomorphic-granular. CF:automorphic
See:xenomorphic
A zero-valent, very heavy, inert gaseous element; one of the so-called
noble gases. Symbol, Xe. Obtained by the fractional distillation of liquid
air. The gas is used in making electron tubes, stroboscopic lamps, and
bactericidal lamps; also used in the atomic energy field in bubble
chambers, probes, and other applications where its high molecular weight
is of value. Handbook of Chemistry and Physics, 3
Said of a hydrothermal mineral deposit formed at high temperature but
shallow depth; also, said of that environment. CF:telethermal;
epithermal; mesothermal; hypothermal deposit; leptothermal. AGI
A tetragonal mineral, YPO4 ; commonly includes small quantities of
thorium, uranium, and rare-earth elements; resembles zircon in form,
structure, and occurrence; shows pale tints; an accessory in granites and
pegmatites; also occurs in placers.
A brace of a square set in which two diagonal pieces of timber cross to
form an X. Fay
A monoclinic and triclinic mineral, Ca6 Si6 O17 (OH)
2 ; light-gray to pink; fibrous; in serpentinites in Santa Barbara,
CA, and on Isle Royale, MI.
Reflection at definite and characteristic angles from space lattices of
crystals of X-rays that have been caused to bombard them, thus giving data
for identification of characteristic lattice structure of a given species
of mineral. See also:reciprocal lattice; diffraction. Pryor, 3
a. A subvariety of provitrain in which the woody origin of the cellular
structure is microscopically visible. CF:periblain; suberain.
AGI
b. Those constituents of coal derived from lignified tissues in which
structures were retained. AGI
A variety of fossil resin. Tomkeieff
A maceral composed of xylain. Tomkeieff
a. A variety of provitrinite. The micropetrological constituent, or
maceral, of xylain. It consists of wood (xylem or lignified tissues)
almost jellified in bulk but still showing faint traces of cell walls and
resin contents under the microcope. AGI
b. A distinction of telinite, based on botanical origin (xylem or
lignified tissues). To be used if desired but considered unnecessary by
the Heerlen Congress of 1935. CF:suberinite; telinite. AGI
See:scheererite
An explosive compound produced by the action of nitric acid on starch or
woody fiber. Resembles guncotton. Fay