Melted Quartz?  What the heck?  What is it?

Quartz is a plentiful mineral found in many rock formations. Rock Crystal as it is traditionally known is pure quartz, colourless and transparent. As these crystals breakdown they create silica sand.  Silica and quartz crystals have very high melting points.  Exposed to extreme heat, the crystals creates molten glass which then can be reshaped before it hardens.