A Geoscience Digital Image Library

TitleMetabasite, Lowell County, Idaho
DescriptionThis rock was labelled a gneiss in the Ward’s Collection of Classic North American Rocks, but shows little of the typical dark and light banding that defines a gneiss. So, we have changed the name and use the term “metabasite” which refers to any metamorphosed mafic rock. The dark green mineral is diopside, the white mineral is plagioclase, and small amounts of hornblende are also present (but not easily seen without a microscope). The sample is 8 cm across.
LocationUSA ▹ Idaho ▹ Lowell
PhotographerMike Davis. 2001-04-26.
CollectionWard’s University Rock Collection #192.
Key wordsdiopside, gneiss, Idaho
Tech details750 KB. Hand specimen. Fujifilm FinePix S1Pro digital camera, 60mm Nikon AF micro lens.
GeoDIL number430