Key Characteristics: Strong brown coloration and plechroism, birds eye and parallel extinction, and high birefringence are diagnostic 2V: 2Vx = 0 - 25° Relief: moderately high positive relief Cleavage: One perfect cleavage Colour and Plechroism: Strongly colored brown, reddish brown, or brownish green in thin section; Stong pleochroism Optical Orientation: Parallel and birds eye extinction Twinning: Not common Optical character: Biaxial(-)
