A Geoscience Digital Image Library

TitleStaurolite in a fine grained mica schist
DescriptionStaurolite, Fe2Al9Si4O22(OH)2,is a common metamorphic mineral that is used by metamorphic geologists to determine the degree of metamorphism. Here, the staurolite is poorly distinguished, appearing as brown rectangular “ghosts” in a sea of fine grained biotite and quartz. This is not an uncommon appearance for staurolite because it often has a drab color and because it alters readily when exposed to air and mosture. Staurolite may exist as individual crystals (as is seen here), but it commonly twins to form cross-shaped compound crystals. This sample is about 5 cm across.
LocationUSA ▹ Minnesota. Near Little Falls.
PhotographerDarla Sondrol. 2001-03-26.
CollectionUniversity of North Dakota Mineralogy Collection #3125.
Key wordsstaurolite
Tech details1.34 MB. Hand specimen. Fujifilm FinePix S1Pro digital camera; 60mm AF Nikon micro lens.
GeoDIL number265