TRIDYMITE on QUARTZ, BRAZIL (large cabinet)

Tridymite is a rare high-temperature form of silica, typically found as small, tabular white or colorless pseudo-hexagonal crystals or scales within cavities of felsic volcanic rocks. Its chemical composition is represented by the formula SiO2. First identified in 1868, the mineral was originally located in Hidalgo, Mexico. The name "tridymite" derives from the Greek word "tridymos," meaning triplet, reflecting its common occurrence in twinned crystal formations known as trillings, which consist of three interconnected crystal components.

Quartz is a robust crystalline mineral made up of silica, or silicon dioxide. Its structure consists of a continuous arrangement of SiO4 silicon-oxygen tetrahedra, where each oxygen atom is shared between two tetrahedra, resulting in the chemical formula SiO2. This classification places quartz as a framework silicate mineral in terms of structure and as an oxide mineral in terms of composition. It ranks as the second most prevalent mineral in the continental crust of Earth, following feldspar.