Quartz crystal

Quartz

Quartz is a tectosilicate mineral that is the second most common mineral in Earth's continental crust. Its crystal structure is a framework of SiO₄silicon–oxygen tetrahedra. Each shares an oxygen atom with another tetrahedron, so the overall chemical formula is SiO₂ or silica.

It's name is derived from the German quarz, which sounds the same but is spelled without a t.