warwickite

{{Infobox mineral | name = Warwickite | boxwidth = | boxbgcolor = | image = Warwickite.jpg | imagesize = | alt = | caption = Warwickite sample | category = Borate mineral | formula = | IMAsymbol = Wwk | molweight = | strunz = 6.AB.20 | dana = | system = Orthorhombic | class = Dipyramidal (mmm) H-M symbol: (2/m 2/m 2/m) | symmetry = Pnam | unit cell = | color = dark brown, grey to black¨ | colour = | habit = | twinning = | cleavage = perfect on {100} | fracture = irregular/uneven | tenacity = | mohs = 3-4 | luster = sub-Vitreous, pearly, sub-metallic, dull | streak = bluish black | diaphaneity = | gravity = 3.34 - 3.36 | density = | polish = | opticalprop = | refractive = | birefringence = | pleochroism = | 2V = | dispersion = | extinction = | length fast/slow = | fluorescence = | absorption = | melt = | fusibility = | diagnostic = | solubility = | impurities = | alteration = | other = | prop1 = | prop1text = | references = }} Warwickite is an iron magnesium titanium borate mineral with the chemical formula or . 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.