The quartz crystal — what’s so special about it?
Quartz is one of the most common crystals in our planet’s crust, consisting of chemical elements (Silicon and Oxygen) that are also very common in our piece. But quartz crystals have fascinated humans for centuries, and several industries have important uses for quartz. So what’s so special about it?
Quartz mineralogy and history
Quartz has been known for a long time. In the 3rd century BC, the philosopher Theophrastus called it “kristallos”, the world that gives us the word “crystal” that we use today. The ancient Greek word hinted at solid ice, as Theophrastus thought quartz was a form of supercooled, permanently solidified ice.
You can’t really blame him. Quartz is remarkably transparent (or translucent), although it can also appear in colored varieties (as we’ll see soon enough).
In the 17th century, Danish scientist Nicolas Steno studied quartz, paving the way for our understanding not just of quartz, but of crystallography in general. He figured out that regardless of a quartz crystal’s size or shape, its long prism faces are always joined at a perfect 60° angle. This suggests that all quartz crystals have a similar, repeating structure.
The mineral itself has a relatively simple structure. Its atoms are linked in a continuous network of tetrahedra, with one atom of Silicon and 4 atoms of Oxygen. However, each oxygen is being shared between two tetrahedra (hence the SiO2 chemical formula).