Diorite


Also found in: Dictionary, Thesaurus, Acronyms, Wikipedia.
Related to Diorite: gabbro, andesite, Quartz diorite

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.

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.

diorite

Medium- to coarse-grained rock composed essentially of plagioclase feldspar and ferromagnesium minerals.
References in periodicals archive ?
The drillhole intersected brecciated and faulted diorite, propylitic altered, and containing quartz-carbonate-pyrite-chalcopyrite veinlets at upper levels with an increase of massive sulphides and copper-gold grades at depth as reported in Table 1.
Gabbro is generally medium to dark grey and the grain size varies from fine to medium; quartz diorite is texturally similar to the gabbro but lighter in colour.
Stephen et de la diorite quartzite de Calais presentent une petrochimie semblable aux parties mafiques et intermediaires du pluton de Bocabec du batholite de Saint George, tandis que le granite de Baring ressemble aux parties granitiques du pluton de Bocabec.
Drilling at Lady Charlotte (immediately to the east of Undaunted) has targeted interpreted diorites around some historical intercepts.
The plutons of the Golden Grove suite can be broadly grouped into four compositional types depending on the dominant rock type, abundance of mafic minerals, and texture: (1) gabbro, (2) diorite to granodiorite, (3) granodiorite to monzogranite, and (4) syenogranite to monzogranite.
Mineralization at the Bee Creek prospect is hosted in hornfelsed sediments intruded by a multiphase diorite intrusive rock containing mineralized veins and disseminated chalcopyrite, molybdenite and pyrite.
The pits intersected the Chimu formation and bottomed in strongly altered diorite intruding the overlying quartzites.
From 80m to 579m depth the hole intersected strongly altered and mineralized diorite porphyry and diorite breccia.
Gold mineralisation is situated in all four trenches concluded, though trenches 1, 3 and 4 did not intercept the quartz diorite intrusion and gold results were lesser.
9 281 Silicified Diorite subcrop with pyrite 8156E 21896 Float-grab 10.
All five holes of the program have been completed and have confirmed that mineralization, including visible gold in some holes, occurs in association with stockwork-type quartz sulphide veining within albitized diorites developed along north-south trending structural corridors.
5- to 20-metre-wide quartz diorite dykes that were emplaced into a series of diorites and quartz diorites.