February's birthstone amethyst is a variety of quartz, as are an awful lot of things. It comes in various shades of purple and violet from very pale to dark.
Whilst amethyst used to be very precious more recently large deposits have been found and it can now be quite affordable. A good variety of stones is available from traceable sources including Nineteen48, Gemstones Brazil and Fair Trade Gemstones.
I would put amethyst along with garnet into the underappreciated category, particularly when set in 9ct gold, it feels a little softer than it does when next to silver.
Rose cut pale amethyst set in sterling silver
Medieval knights wore amethyst amulets in the belief they would protect the bearer from injury and keep the wearer cool headed. If worn whilst sleeping the stone is thought to reduce anger and impatience.
Amethyst solitaire pendant
The name comes from ancient Greek, the stone is associated with the god Bacchus, and the name is a reference to the fact that apparently wearing the stone can help protect from drunkenness. It has been used in jewellery since ancient Egyptian times, and was often carved into elaborate intaglio gems.
Amethyst cabochon in 9ct yellow gold stacking ring
Faceted amethyst in sterling silver stacking ring