pigeonite

augite

olivine

monzonite

Pigeonite

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Formula: (Mg,Fe,Ca)2Si2O6
Inosilicate (chain silicate), clinopyroxene
Specific gravity: 3.3 to 3.46
Hardness: 6
Streak: Greyish white
Colour: Black, brown, greenish brown
Common impurities: Ti,Al,Mn,Na,K,H2O
Environments:

Igneous environments
Metamorphic environments
Extraterrestrial environments

Pigeonite is a high-temperature mineral, forming mostly above 900°C, and with slow cooling it tends to invert to a mixture of augite and orthopyroxene. Thus it is mostly restricted to volcanic and subvolcanic rocks like basalt and dolerite (Mindat). Inverted varieties with exsolved augite are found in layered mafic intrusives. It also occurs in metamorphosed iron formations and meteorites. Associated minerals include augite and olivine (HOM).

Localities

At the Pigeonite occurrence, Cherry Hill, Lunenburg county, Nova Scotia, Canada, pigeonite occurs in monzogranite and monzonite (Dana).

At Weißelberg, Oberkirchen, St Wendel, Saarland, Germany, pigeonite occurs in andesite (Dana).

At Mount Hakone, Ashigarakami District, Kanagawa Prefecture, Japan, pigeonite occurs in andesite (Dana).

At Mt. Mihara, Oushima Island (Ohshima; Oshima), Izu Archipelago, Tokyo, Japan, pigeonite occurs in basalt (Dana).

On the Isle of Mull, Argyll and Bute, Scotland, UK, pigeonite occurs in andesite (Dana).

At the type locality, Pigeon Point, Cook county, Minnesota, USA, in pigeonite occurs in dolerite (Dana).

At Biwabik, Mesabi Range, St. Louis county, Minnesota, USA, Mn-rich pigeonite occurs as a product of prograde metamorphism in the iron formation (Dana).

At Lambertville, Hunterdon county, New Jersey, USA, pigeonite occurs in dolerite (Dana).

At Goose Creek, Leesburg, Loudoun county, Virginia, USA, pigeonite occurs in a dolerite pegmatite (Dana).

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