cristobalit
Cristobalite, also spelled cristobalit in some languages, is a mineral form of silica (SiO2) and a high-temperature polymorph of quartz. It is one of the crystalline forms of silica distinct from quartz and tridymite and is stable at high temperatures and low pressures; at ambient conditions it can be metastable and slowly transform to quartz in nature.
Natural occurrence: Cristobalite forms in volcanic rocks and glassy silica-rich materials, particularly in volcanic ash, pumice,
Physical properties: It is typically colorless to white, with a vitreous luster and transparent to translucent
Industrial and geological significance: Natural cristobalite is important for mineralogists and volcanologists as an indicator of
Health considerations: Inhalation of respirable cristobalite dust poses a risk of silicosis and other lung diseases;