The amazing crackle effect is created when the rock crystal is heated to a temperature that causes the stone to crackle on the inside. The finished product is stable, durable, and has alluring patterns.
The name “rock crystal” emerged in late Medieval Europe to differentiate this gemstone from newly perfected colorless glass, to which the name crystal, or crystal glass was attached. Rock Crystal is the clear, colorless variety of macrocrystalline quartz (silicon dioxide). Rock crystal often has inclusions of other minerals. Needle-like inclusions of golden rutile produce rutilated quartz.