Key Characteristics: The high relief, lack of cleavage, crystal form and high birefringence are all diagnostic 2V: 2Vx = 46 - 98° Relief: High positive relief Cleavage: Cleavage not visible in thin section; Grains are commonly fractured and display actively alter to iddingsite and serpentine Colour and Plechroism: Usually colorless, may be very pale green depending upon mineral's iron content Optical Orientation: Parallel extinction Twinning: Not common Optical character: Biaxial (-) or (+)
