Porphyrite

Definitions

  • Webster's Revised Unabridged Dictionary
    • n Porphyrite (Min) A rock with a porphyritic structure; as, augite porphyrite .
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Century Dictionary and Cyclopedia
    • n porphyrite The name given to those porphyries in which the ground-mass consists chiefly of a triclinic, feldspar, together with either augite or hornblende, or, in some cases, of biotite: in this ground-mass larger crystals of the same species are porphyritically developed. The porphyrites are classed by some authors as diorite- or diabase-porphyrites: in the former the ground-mass contains hornblende; in the latter, augite in connection with the plagioclase. With these occur certain accessory minerals, such as magnetite, titaniferous iron, etc. Various names are given to these rocks, in accordance with the nature of the minerals porphyritically developed in the ground-mass, as hornblende porphyrite, mica porphyrite, augite porphyrite, etc.
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Chambers's Twentieth Century Dictionary
    • n Porphyrite one of the crystalline igneous rocks, which consists principally of plagioclase
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Etymology

Chambers's Twentieth Century Dictionary
Through Fr. and L. from Gr. porphyritesporphyra, purple.

Usage

In literature:

Long before this it existed as a slate and porphyritic line of hills.
"More Letters of Charles Darwin" by Charles Darwin
The soil, in fact, was bestrewn with quartz and porphyritic rocks.
"Five Weeks in a Balloon" by Jules Verne
A Porphyritic sienite cropped out at the head of the first swamp, about a mile from our last camp.
"Journal of an Overland Expedition in Australia" by Ludwig Leichhardt
But the bulk of the moraine is composed of porphyritic granite derived from Feldspar and Cathedral Valleys.
"The Yosemite" by John Muir
Porphyritic Conglomerate: C. Clinton, Percy I., Good's I.
"Narrative of a Survey of the Intertropical and Western Coasts of Australia] [Volume 2 of 2]" by Phillip Parker King
Other summits of the range are porphyritic,** but the hills of Wingen present a variety of rocks, within a small space.
"Three Expeditions into the Interior of Eastern Australia, Vol 1 (of 2)" by Thomas Mitchell
The lowest rock I saw was a compact porphyritic one.
"Journals Of Two Expeditions Of Discovery In North-West And Western Australia, Vol. 2 (of 2)" by George Grey
Whiche Porphyrite was three foote from the playne ouermost parte to the Pauement, with an excellent vndiculation.
"Hypnerotomachia" by Francesco Colonna
It is made of a remarkable variety of porphyritic diorite that resembles breccia.
"Illustrated Catalogue of a Portion of the Collections Made" by William H. Holmes
The roadway, paved with well-cut, dark porphyritic stone, was twenty feet wide, and rested on deep foundations.
"Ancient America, in Notes on American Archaeology" by John D. Baldwin
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In poetry:

The trachyte wall, beseamed and battle scarred;
The porphyritic tower and citadel;
The granite ramparts and embattlements
Of nature's fort, impregnable and wild,
Stand as a symbol of eternal strength,
And hurl a challenge to the elements!
"Grandeur." by Alfred Castner King

In news:

According to Jim Howle, a hydrologist/geologist with the US Geological Survey, a 2 million-year-old pinkish porphyritic andesite used in North Shore houses came from volcanic flows from Mount Watson near Tahoe City.
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In science:

Fig. 3. Scanning electron micrographs of chondrules and CAIs. A. Porphyritic Olivine type I chondrule. B. Porphyritic Olivine Pyroxene type I chondrule. C. Porphyritic Pyroxene type I chondrule. D . Barred O liv ine type I chondrule. E. Porphy ritic O liv ine type II chondrule. F . Amoeboid Olivine Aggregate. G.
Meteorites and the physico-chemical conditions in the early solar nebula
Porphyritic type I chondrules vary from olivine-rich (PO) to pyroxene-rich (PP) with intermediate members rich in olivine and pyroxene (POP).
Meteorites and the physico-chemical conditions in the early solar nebula
Typical porphyritic textures are produced by a subsequent melting episode in the presence of Ca-rich pyroxene and anorthite (Whattam and Hewins 2008).
Meteorites and the physico-chemical conditions in the early solar nebula
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