WGNHS
Wisconsin Geological and Natural History Survey

Pigeonite

Blue bands of pigeonite in clinopyroxene with plagioclase feldspar (pale blue grains with barred patterns). Image is from a thin section viewed in cross-polarized light at 10x magnification, field of view is about 2 mm. (Photo courtesy Alex Strekeisen; unauthorized reproduction is prohibited.)

Formula: (Mg,Fe,Ca)(Mg,Fe)Si2O6 Monoclinic

Description:

Pigeonite is a member of the pyroxene group found generally as small grains in gabbros, basalts, andesites, dacites and hornfels. It occurs with plagioclase and augite, and is difficult to identify. It is probably more common in the state than indicated by the reported locality.

ASHLAND COUNTY: Pigeonite occurs as tiny grains in hornfels of the Ironwood iron formation in contact with the Mellen gabbro seen in outcrop in the SE NE sec. 14 T.44N. R.4W. It is associated here with fayalite, ferroaugite, orthopyroxene, magnetite and grunerite (Laybourn, 1979).