ulexite
noun/ˈjulɛksaɪt/ · /juˈlɛkˌsaɪt/
Etymology Named after the German chemist Georg Ludwig Ulex (1811-1883) + -ite.
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Chemistry, Geography, Geology, Mineralogy, Natural sciences, Physical sciences A white mineral with triclinic crystals, NaCaB₅O₉·8H₂O, noted for its fibers which transmit light by internal reflection, such that a piece with flat faces perpendicular to the fibers' orientation displays an image of whatever is adjacent to its other side.