The staurolite is a hydrous silicate mineral of aluminum and iron. It belongs to the monoclinic or pseudorhombic crystal system. The crystals are well developed and are short columnar. They usually have a cross with an angle of 90° or an X with an angle of 60°. Shape through the double crystal. The staurolite has glass luster to rosin luster, transparent-translucent-opaque, and the hardness is 7.0-7.5. Its color is dark brown, reddish brown, yellowish brown to black brown and has pleochroism, yellow or red, golden yellow and colorless.
The staurolite has no beautiful color, characteristic inclusions, and no fluorescence, but because it is rare, has a greater hardness, and especially has a peculiar cross-shaped appearance, it has also been loved by people in the West for hundreds of years. Always wear it as an amulet or as religious jewelry. The transparent staurolite crystal is regarded as a good product, which can be processed into faceted gems, which is very precious and is generally used for viewing or collecting. Crucifixite treasures are rare. A dark brown precious crucifixite crystal, weighing 3 カラット, is collected in the Smithson Museum in Washington, アメリカ合衆国, and is produced in Brazil. The unique shape of staurolite makes it not similar to gemstones, but there are fakes. It is made of other materials through corrosion or carving. Because its hardness and specific gravity are lower than staurotus, it is not difficult to distinguish.
Staurolite is produced in metamorphic rocks such as gneiss, crystalline schist and phyllite. It is a deep metamorphic mineral. It is usually symbiosis with minerals such as kyanite, トルマリン, garnet and sillimanite, and is also found in secondary placers. Among. The world’s famous producers of staurolite include Switzerland, フランス, Namibia, ブラジル, the United States and Mexico, 等. The gem-grade staurolite crystals are produced in Switzerland and Brazil, and the double crystals are mostly produced in the United States.