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Pyroxene crystals from AfghanistanThe pyroxenes (commonly abbreviated Px) are a group of important rock-forming inosilicate minerals found in many igneous and metamorphic rocks.
Euhedral crystal of augite from Teide (4.4 x 3.0 x 2.3 cm). Augite is a solid solution in the pyroxene group. Diopside and hedenbergite are important endmembers in augite, but augite can also contain significant aluminium, titanium, and sodium and other elements.
Pleochroism is an extremely useful tool in mineralogy and gemology for mineral and gem identification, since the number of colors visible from different angles can identify the possible crystalline structure of a gemstone or mineral and therefore help to classify it. Minerals that are otherwise very similar often have very different pleochroic ...
Aegirine is a member of the clinopyroxene group of inosilicate minerals. It is the sodium endmember of the aegirine–augite series. It has the chemical formula NaFeSi 2 O 6, in which the iron is present as the ion Fe 3+.
Omphacite is a member of the clinopyroxene group of silicate minerals with formula: (Ca, Na)(Mg, Fe 2+, Al)Si 2 O 6. It is a variably deep to pale green or nearly colorless variety of clinopyroxene. It normally appears in eclogite, which is the high-pressure metamorphic rock of basalt. Omphacite is the solid solution of Fe-bearing diopside and ...
Diopside is a monoclinic pyroxene mineral with composition MgCaSi 2 O 6.It forms complete solid solution series with hedenbergite (FeCaSi 2 O 6) and augite, and partial solid solutions with orthopyroxene and pigeonite.
Pigeonite is a mineral in the clinopyroxene subgroup of the pyroxene group. It has a general formula of (Ca,Mg,Fe)(Mg,Fe)Si 2 O 6.The calcium cation fraction can vary from 5% to 25%, with iron and magnesium making up the rest of the cations.
Purely pyroxene-bearing volcanic rocks are rare, restricted to spinifex-textured sills, lava tubes and thick flows in the Archaean greenstone belts.Here, the pyroxenite lavas are created by in-situ crystallisation and accumulation of pyroxene at the base of a lava flow, creating the distinctive spinifex texture, but also occasionally mesocumulate and orthocumulate segregations.