QUARTZ with CALCITE (cabinet)

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.

Calcite is a carbonate mineral and the most stable form of calcium carbonate (CaCO3). It is widely found, especially as a key element in limestone. With a hardness rating of 3 on the Mohs scale, calcite is assessed based on its ability to be scratched. Large crystals of calcite are utilized in optical devices, while limestone, primarily made up of calcite, serves a variety of purposes.