One type of this mineral created in high pressures is abundant near the K-T boundary.
The alpha type of this mineral crystallizes trigonally and the beta type crystallizes hexagonally. Cristobalite has the same chemical formula but different crystal structure than this mineral. One type of this mineral created in high pressures is abundant near the K-T boundary. This mineral is found under muscovite on the Bowen's Reaction Series, and, like Topaz, this mineral is piezoelectric. Forms of this mineral include amethyst, and trace amounts of titanium create the rose type of this mineral. For 10 points, name this mineral that scores a 7 on the Mohs hardness scale, and which is composed of silicon dioxide.
The alpha type of this mineral crystallizes trigonally and the beta type crystallizes hexagonally.
quartz