A term proposed by Barth (1962) for the redistribution of granitizing
materials within sediments by mobilization, transfer, and reprecipitation,
as opposed to metasomatism involving addition of new materials.
AGI
a. An old term for altered glassy trachyte.
b. Iron meteorite with the composition of an octahedrite but lacking
Widmaenstatten figures.
An isometric mineral, HBO2 ; in crystalline aggregates in rock salt
in Kazakhstan(?).
See:brushite
A term proposed by Dana to describe metamorphism that involves a chemical
change in the affected rocks.
An isometric mineral, HgS ; forms black tetrahedra; sp gr, 7.7; a source
of mercury. Also called metacinnabarite. Also spelled: metacinnibar
A mineral of the same composition as a cinnabar, but black in color, and
crystallizing in isometric forms (tetrahedral). Used as a source of
mercury. Sanford
Leith's term for a rock possessing secondary cleavage, or cleavage in its
modern meaning (1905). CF:protoclase
Any large crystal developed in a metamorphic rock by recrystallization,
such as garnet or staurolite in mica schists.
See:porphyroblast
A contraction of metamorphic diabase, suggested by Dana for certain rocks
simulating diabase, but which were possibly produced by the metamorphism
of sedimentary rocks. CF:metadiorite
a. A contraction of metamorphic diorite that was proposed for certain
metamorphic rocks that resemble diorite, but which may have been the
result of the metamorphism of sedimentary rocks. CF:metadiabase
Fay
b. Metamorphosed gabbro, diabase, or diorite. AGI
A metamorphic dolomite, or dolomite marble.
Durain of a high-rank bituminous coal. See also:durain
Tomkeieff
A hieroglyph formed during metamorphism. Pettijohn, 1
Dehydrated halloysite. See also:halloysite
A tetragonal mineral, Ba(UO2 )2 (AsO4 )2 .8H
2 O ; meta-autunite group; yellow; a secondary mineral.
Syn:arsenuranocircite; metasandbergite. CF:heinrichite
A monoclinic mineral, CaV6 O16 .3H2 O ; dark-red to
yellow-brown; forms tabular crystals impregnating sandstone in southwest
Colorado and southeast Utah. CF:hewettite
A mineral, Fe2 (SO4 )2 (OH)2 .3H2 O .
See also:hohmannite
A hydrous calcium and magnesium borate, CaMgB6 O8 (OH) (sub
6) .XH2 0 ; like hydroboracite but with more water.
Syn:inderborite
A tetragonal mineral, Fe(UO2 )2 (AsO4 )2 .8H
2 O; meta-autunite group.