Diorite

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diorite

[′dī·ə‚rīt]
(petrology)
A phaneritic plutonic rock with granular texture composed largely of plagioclase feldspar with smaller amounts of dark-colored minerals; used occasionally as ornamental and building stone. Also known as black granite.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Diorite

 

a magmatic rock composed of plagioclase (andesine or oligoclase), hornblende, and more rarely, augite and biotite; sometimes quartz is present. Chemically, diorite is characterized by an average amount of silicic acid (55-65 percent).

Several varieties of diorite may be distinguished: quartz, quartzless, hornblende, augite, and biotite. Its color is gray to greenish-gray, and its structure is characterized by clearly defined idiomorphic plagioclase, which distinguishes it from biotite and amphibole. Diorite is not widespread and as a rule is found with granites and granodiorites, more rarely with other rock; it appears as a local facies.,In addition diorite may form independent stocks, veins, laccoliths, and other intrusive massifs. It is used as a building material and in road building. Some varieties of diorite have many shades of color and lend themselves to polishing; these are used to face buildings and to make such articles as vases, table tops, and pedestals. In ancient Egypt and ancient Mesopotamia diorite was also used for sculpture. Hard, dense, and opaque, diorite is used as a general-purpose sculptural stone to create forms of severe structural design; it also used in fine graphic-linear cutting.


Diorite

 

magmatic rock of paleotype habit, similar to basalt chemically and in its mineral composition. Diorite is characterized by a relatively small silica content (45-52 percent). Its coloring is dark gray or greenish black. The dioritic (ophitic) structure is formed by randomly placed elongated small plagioclase crystals, with augite in the interstices. Diorite is especially distributed in regions with gently sloping stratification of the sedimentary rock that encloses it, as well as among volcanic lava and tufa. Diorites form shallow, congealed bodies (sills and dikes) whose depth varies from a few cm to 200 m or more. Diorite is used for road-building stone and for stone casting.

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.

diorite

Medium- to coarse-grained rock composed essentially of plagioclase feldspar and ferromagnesium minerals.
McGraw-Hill Dictionary of Architecture and Construction. Copyright © 2003 by McGraw-Hill Companies, Inc.
References in periodicals archive ?
Drilling at Undaunted targeted previous intercepts from earlier in the year (see ASX release dated 01/03/11) and has identified a mineralised diorite with a strike length of 150m returning significant intercepts including: 16m @ 2.7g/t, 6m @ 4.5g/t and 6m @ 3.1g/t.
The intrusive body belongs to a set of intermediate-acid composite rock body, which mainly includes quartz diorite, granodiorite, quartz diorite, aplite, etc.
A late influx of mafic magma disrupted older mafic rocks and hybridised with granite, producing complex, heterogeneous "diorite".
Post-metamorphic Late Silurian plutons of intermediate to granitic composition, including the 430[+ or -]5 Ma Sharpners Pond Diorite (Zartman and Naylor 1984), intruded the metasedimentary rocks of the Putnam-Nashoba terrane (Loftenius 1988).
While the rocks of Kohistan paleo-arc in the study area are the volcanic rocks of the Chalt Volcanic Group (CVG) the meta-sediments of the Yasin Group and the diorites of Kohistan batholith.
Relatively dark colored gabbroic- diorites have high proportion of hornblende and micaceous minerals (mainly biotite).
The geology of the study area consists of meta-sediments and meta-volcanics intruded by diorites belonging to the Kohistan batholith.
Sulfide mineralization occurs in association with diorites and quartz veins, along foliation planes, as dissemination and as supergene enrichment.
The Kohistan sequence represents rocks of a young arc crust comprising amphibolites, diorites, metanorites and associated volcanic rocks.
The ore bodies in the J4 zone are hosted in the northern continuity of the Troilus Diorite and, similarly to what is observed in the main zones Z87 and Z87 South, are elongated parallel to a penetrative NE-trending foliation, moderately to steeply dipping to the north west.