tridymite

English Thesaurus

1. a mineral form of silica (noun.substance)

hypernym	:	mineral,
definition	:	solid homogeneous inorganic substances occurring in nature having a definite chemical composition (noun.substance)

substance holonym	:	silica, silicon dioxide, silicon oxide,
definition	:	a white or colorless vitreous insoluble solid (SiO2); various forms occur widely in the earth's crust as quartz or cristobalite or tridymite or lechatelierite (noun.substance)