staurolite

stau·ro·lite

noun \ˈstȯr-ə-ˌlīt\

Definition of STAUROLITE

: a mineral consisting of a basic silicate of iron and aluminum in prismatic orthorhombic crystals often twinned so as to resemble a cross

— stau·ro·lit·ic \ˌstȯr-ə-ˈli-tik\ adjective

Origin of STAUROLITE

French, from Greek stauros cross + French -lite — more at steer

First Known Use: circa 1815

staurolite

noun    (Concise Encyclopedia)

Silicate mineral produced by regional metamorphism in rocks such as mica schists, slates, and gneisses, where it is generally associated with other minerals. Staurolite is a brittle, hard mineral that has a dull lustre. Its crystals are usually dark brown and are often twinned in cruciform patterns (known as fairy crosses) that can be made into ornaments. Staurolite occurs especially in Canada, Brazil, France, Switzerland, and the U.S. (North Carolina, Virginia, and Georgia).