This is an ultra unique crystal skull carved from a large piece of Clear Quartz. This piece has been carved with an open mouth which requires no small amount of skill to do well, the overall effect is more realistic and three dimensional.
Quartz is the second most abundant mineral in the Earth's continental crust, after feldspar. There are many different varieties of quartz, several of which are semi-precious gemstones. Common names for the Clear or Translucent variety includes; Rock Crystal, Pure Quartz and Clear Quartz.
Especially in Europe and the Middle East, varieties of quartz have been since antiquity the most commonly used minerals in the making of jewelry and hard-stone carvings.