Cristobalite and tridymite are polymorphs of this mineral, along with its h
Cristobalite and tridymite are polymorphs of this mineral, along with its hexagonal beta variety. A felsic mineral, it lies below muscovite at the bottom of Bowen's reaction series. One variety with planar deformation features is often present in nuclear bomb impact sites and at the K-T boundary, the shocked variety. Like topaz, it exhibits piezoelectricity. Gold ore sometimes occurs in veins of this mineral. It comes in many colored varieties, including onyx, citrine, agate, and amethyst. For 10 points, name this silicate mineral with a Mohs hardness of 7.
Cristobalite and tridymite are polymorphs of this mineral, along with its hexagonal beta variety.
{quartz} [prompt on {silicate}, prompt on {silicon dioxide} or {silica}]