Amethyst is a mineral with a hardness of 7 out of 10 on the Mohs scale of mineral hardness [?]. These Trigonally structured gems are made of silicon dioxide, their full chemical compound being SiO2.
Amethyst is the most coveted stone in the quartz group, and it is sometimes confused with beryl. It is usually found layered with milky quartz, and its color varies from purple to violet.
It is sometimes sold as Ametrine, but this is actually a combined variation of 2 gems; Amethyst and Citrine.
Amethyst like Agate Chalcedony can be found in geodes.
There are many types of synthetic Amethyst around today, so make sure you ask before you buy.
Like Tourmaline and Tanzenite, Amethyst is often heat treated to change its hue.
A funny and strange historical fact is that Amethyst comes from the Greek word methystos which literally means not drunk. It was worn or carried in ones pockets to prevent drunkenness. :)
Purple Amethyst has been coveted for centuries by Royalty and the Christian Church. Purple is the standard royal color, so this gemstone matches well with this scheme.
Quartz in general is used to create optics, glass, beads, circuit boards, sandpaper, and certain electronic devices.