Amethyst are varieties of this mineral, and these minerals appear at the very bottom of Bowen's reaction series.
A thin layer of one of these minerals placed perpendicular to an electric arc served as both a transmitter and a receiver in a sonar apparatus designed by Paul Langevin.These minerals are among the least resistant to weathering. These minerals are found along with moganite in chalcedony, and they generate a charge when mechanically stressed. Citrine and (*) Amethyst are varieties of this mineral, and these minerals appear at the very bottom of Bowen's reaction series. These minerals are piezoelectric, and after feldspars, these are the most abundant minerals on Earth. For 10 points, name this class of minerals which has the empirical formula SiO2.
A thin layer of one of these minerals placed perpendicular to an electric arc served as both a transmitter and a receiver in a sonar apparatus designed by Paul Langevin.
quartz [prompt on silicon dioxide or SiO2 until the last word]