Quartz is the most common mineral in the earth's crust and as a gem it is also the most commonly used of the minerals. In the form of minute dust particles in the air, it scratches other gemstones of lesser hardness.
It is found in a greater variety of forms, modes of occurrence and names than any other mineral.
The transparent colorless variety of quartz is known as rock crystal. Long ago, people believed that rock crystal was a compact form of ice: «Krystallos» actually means «clear ice».
The Chinese believed that rock crystal quenched thirst when held in the mouth.
Using a gazing globe made out of rock crystal, future was foretold by magicians from all over the world.
Even now many people believe that wearing quartz crystals benefits a person's health and spiritual well being.
The name quartz is an old German mining term of unknown meaning that has been in general use since the sixteenth century.