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Like spar; foliated or lamellar; spathose. Spathic iron (Min.), siderite. See Siderite (a).

Pertaining to, or consisting of, feldspar.

See Feldspathic.

An igneous rock of feldspathic composition, lamellar in structure, and clinking under the hammer. See Phonolite.

Of or pertaining to certain veins of feldspathic or porphyritic rock crossing metalliferous veins in the mining districts of Cornwall; as, an elvan course.

A compact feldspathic rock; felsite. See Felsite.

A compact, feldspathic, igneous rock containing nephelite, haüynite, etc. Thin slabs give a ringing sound when struck; -- called also clinkstone.

used somewhat loosely to designate a rock consisting of a fine-grained base (usually feldspathic) through which crystals, as of feldspar or quartz, are disseminated. There are red, purple, and green varieties, which are highly esteemed as marbles. Porphyry shell (Zoöl.), a handsome marine gastropod shell (Oliva porphy…

n rhombohedral crystals. It is of a light yellowish brown color. Called also sparry iron, spathic iron.

See Spathic.

sed to designate various dark- colored, heavy igneous rocks, including especially the feldspathic- augitic rocks, basalt, dolerite, amygdaloid, etc., but including also some kinds of diorite. Called also trap rock. Trap tufa, Trap tuff, a kind of fragmental rock made up of fragments and earthy materials from trap rocks…