31. Tourmaline is notable for exhibiting strong pleochroism.32. Brazilianite also found with tourmaline and feldspar. 33. Matthew Forster Heddle found the quarry a good source for the minerals tourmaline and beryl. 34. The inventor of a new polarizing medium, as an efficient substitute for the Tourmaline . 35. "There's a growing interest in colored gemstones like citrine and pink tourmaline . 36. Portnoy was keen to find something more unusual, a tourmaline or perhaps some green apatite. 37. Another highly valuable variety is chrome tourmaline , a rare type of dravite tourmaline from Tanzania. 38. Another highly valuable variety is chrome tourmaline, a rare type of dravite tourmaline from Tanzania. 39. Tourmaline also occurs in some aplites.40. Associated minerals include beryl, phenakite, herderite, tourmaline , muscovite, fluorite and quartz.
