warwickite

from The Century Dictionary.

• noun A borotitanate of magnesium and iron, occurring in dark-brown to black acicular crystals embedded in granular lime stone. Named from the locality of its occurrence, near Warwick, New York.

from the GNU version of the Collaborative International Dictionary of English.

• noun (Min.) A dark brown or black mineral, occurring in prismatic crystals imbedded in limestone near Warwick, New York. It consists of the borate and titanate of magnesia and iron.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun mineralogy An iron magnesium titanium borate mineral occurring as brown to black prismatic orthorhombic crystals.