Pyrope


Also found in: Dictionary, Thesaurus, Wikipedia.
Related to Pyrope: almandine

pyrope

[′pī‚rōp]
(mineralogy)
Mg3 Al2(SiO4)3 A mineral species of the garnet group characterized by a deep fiery-red color and occurring in basic and ultrabasic igneous rocks.

Pyrope

 

a mineral of the garnet group; in pure form, magnesium aluminum garnet Mg3Al2[SiO4]3, containing 20.45 percent MgO and frequent admixtures of Fe, Mn, and other elements. Known for its rich, attractive dark red color, pyrope is a characteristic component of certain peridotites, kimberlites, and serpentinites. Transparent blood-red varieties of pyrope are classed as gems. The most well-known pyropes are from the Czechoslovak Socialist Republic, where they occur in basalt breccia detritus, embedded in peridotites, and are extracted from placers. In the USSR, pyrope occurs in the kimberlites (where pyrope is associated with diamond) and eclogites of the Yakutia.

References in periodicals archive ?
The value of the bulk modulus in this study for [Mg.sub.3][Y.sub.2][(Si[O.sub.4]).sub.3] is smaller than that of pyrope reported previously, which can be attributed to the different ionic radii and electronegativity.
This is a more purplish or claret colour than pyrope.
About the same time Brian Mason, then curator of the National Collection of Meteorites, considered re-analysis of hornblende and pyrope from Kakanui, New Zealand.
Aluminian-series garnets (Pinet and Smith, 1994) Spectral This Band range Spessartine Almandine Pyrope work symmetry 1100-750 1030 1038 1062 1028 [T.sub.2g] 906 915 924 918 [T.sub.2g] 850 862 867 861 [T.sub.2g] 750-450 632 630 648 633 [T.sub.2g] 553 557 561 557 [A.sub.1g] 503 499 511 500 [T.sub.2g] 450-120 375 370 380 374 [T.sub.2g] 352 345 364 347 [A.sub.1g] 224 216 208 217 [T.sub.2g] 175 168 174 171 [T.sub.2g]
More outcrops of the Dora Maira high-pressure pyrope in quartz are found in the next valley to the south, Val Varaita, in the vicinity of Brossasco.
Kimberlite indicator minerals, including pyrope garnet, chromite, picro-ilmenite, chrome diopside, and olivine were recovered from 356 samples.
On my second visit to Gilbert Gauthier's booth, I noticed some pyrope garnet specimens from the high-pressure metamorphic environment at Casa Parigi, Pidma, Italy.
Apart from diamonds, high-pressure minerals such as pyrope garnet, picroilmenite and chrome diopside occur and are useful indicators in regional exploration.
Occurrence: As inclusions in pyrope megablasts from coesitebearing metamorphic terrane.
About a year ago a chromium mine near Gulbahar, Ghazni Province, Afghanistan produced generous numbers of matrix garnet specimens sporting bright apple-green, in some cases gemmy dodecahedral crystals of a garnet species which some dealers in Tucson were calling pyrope. However, according to Francois Lietard, who has had specimens tested at the Smithsonian and in Europe, the mineral is andradite.
The area is well-known for many classic occurrences of zeolites, and as a famous source of red pyrope ("Bohemian garnet") transported from original peridotitic xenolites into the alluvial deposits where they are found.
The discoverers of the pipe, Alister Fincham and Ernest Schwabel, had been working a claim there for asbestos, but when they found garnets in the soil they suspected the presence of underlying kimberlite (pyrope being a major "indicator" mineral).