Warwickite

Warwickite is an iron magnesium titanium borate mineral with the chemical formula (MgFe)3Ti(O, BO3)2 or Mg(Ti,Fe(3+), Al)(BO3)O. It occurs as brown to black prismatic orthorhombic crystals which are vitreous and transparent. It has a Mohs hardness of 3 to 4 and a specific gravity of 3.36.

Occurrence
It occurs metasomatized limestone skarns and in lamproite and carbonatite veinlets. It was first described in 1838 near Warwick, Orange County, New York. It has also been reported from Bancroft, Ontario; in Murcia Province, Spain; in Siberia and near Pyongyang, North Korea.