Staurolite

Staurolite is a popular mineral composed of aluminum iron silicate. ^[1]

Staurolite: Quick Facts and Characteristics

Some quick facts for Staurolite:

• Transparency: Staurolite can be opaque, translucent or transparent.
• Crystallography: In terms of crystallography, staurolite can be monoclinic or orthorhombic.
• Luster: In terms of luster, staurolite can be dull, resinous or vitreous (glassy).
• Streak: Staurolite streaks white.
• Hardness: Staurolite's hardness ranges from 7 to 7.5 on the Moh's scale.
• Specific Gravity: Staurolite's specific gravity ranges from 3.65 to 3.83.

Staurolite: Background and Summary

Staurolite is a mineral that belongs to the family of nesosilicates, with the chemical formula Fe2+2Al9Si4O23(OH). It is commonly found in metamorphic rocks such as schist and gneiss, and is known for its distinctive cross-shaped twinning, which is why it is sometimes referred to as "fairy crosses." The name staurolite is derived from the Greek words "stauros" meaning cross and "lithos" meaning stone.

Staurolite is typically brown or black in color and has a hardness of 7-7.5 on the Mohs scale. It has a specific gravity of 3.5-3.8 and is often found in prismatic or tabular crystals. To identify staurolite, it is important to look for its characteristic cross-shaped twinning, which can be seen in thin sections under a microscope. Staurolite can also be distinguished from other minerals by its high iron content and its association with metamorphic rocks.

Staurolite has several uses in industry and in the field of mineralogy. It is sometimes used as a gemstone or for ornamental purposes due to its unique twinning. It is also used in the manufacture of abrasives, such as sandpaper and grinding wheels, due to its hardness and durability. In addition, staurolite is used in the production of refractory materials, which are used to line high-temperature industrial furnaces.