A mineral of a brown to black color occurring in prismatic crystals, often twinned so as to form groups resembling a cross. It is a silicate of alumina and iron, and is generally found imbedded in mica schist. Called also granatite, and grenatite.
These stones are twinned crystals which form into equal-armed crosses or x-shapes. At least three presidents of the United States carried these, including Roosevelt, Wilson, and Harding. Staurolite crystals are thought to protect and guard against negativity. They are also worn to draw wealth and energize the sexual drive.
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 a rather complex chemical formula: (Fe,Mg,Zn)2Al9(Si,Al)4O22OH2. Iron, magnesium and zinc occur in variable ratios.