Warwickite

Warwickite is an iron magnesium titanium borate mineral with the chemical formula (MgFe)₃Ti(O, BO₃)₂ or Mg(Ti,Fe³⁺, 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.^[3][4]

Warwickite
Warwickite sample
General
Category	Borate mineral
Formula	(Mg,Fe2+)3Ti[O,BO3]2
IMA symbol	Wwk[1]
Strunz classification	6.AB.20
Crystal system	Orthorhombic
Crystal class	Dipyramidal (mmm) H-M symbol: (2/m 2/m 2/m)
Space group	Pnam
Identification
Color	dark brown, grey to black¨
Cleavage	perfect on {100}
Fracture	irregular/uneven
Mohs scale hardness	3-4
Luster	sub-Vitreous, pearly, sub-metallic, dull
Streak	bluish black
Specific gravity	3.34 - 3.36
References	[2]

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.^[5]