Staurolite (nonfiction)

Staurolite is a red brown to black, mostly opaque, nesosilicate mineral with a white streak. It crystallizes in the monoclinic crystal system, has a Mohs hardness of 7 to 7.5 and the chemical formula: Fe2+2Al9O6(SiO4)4(O,OH)2. Magnesium, zinc and manganese substitute in the iron site and trivalent iron can substitute for aluminum.

Staurolite often occurs twinned in a characteristic cross-shape, called cruciform penetration twinning. In handsamples, macroscopically visible staurolite crystals are of prismatic shape. The mineral often forms porphyroblasts.

Fiction cross-reference

• Gnomon algorithm
• Gnomon Chronicles

External links

• https://en.wikipedia.org/wiki/Staurolite
• https://www.royaltonmn.com/vertical/sites/%7BF29AE369-80CF-4CFB-BE87-851B6F04B18E%7D/uploads/Cross_Rock_Directions.pdf
• https://www.royaltonmn.com/vertical/sites/%7BF29AE369-80CF-4CFB-BE87-851B6F04B18E%7D/uploads/Area_Map_with_cross_rock_location(1).pdf
• http://www.findingrocks.com/cgi-bin/viewlocation.cgi?location_id=185