herapathite
noun
her·a·path·ite
ˈherəˌpaˌthīt,
-pȧˌ-
plural -s
: a salt of quinine that is obtained by treating the sulfate with iodine in the form of rhomboidal plates capable of polarizing light and that is used as a polarizing agent usually in the form of small crystals oriented in the same direction in a transparent film
Word History
Etymology
William B. Herapath †1868 English chemist + English -ite