Amethyst is one of the most precious and valuable stones belonging to the quartz group of minerals, with exception to rare blue-green gem silica. It is recognized as the official birthstone for the month of February. Amethyst belongs to the macrocrystalline branch of quartz and owes its violet/purple color to iron and aluminum impurities. Without such coloring agents, amethyst would simply be transparent, ordinary colorless quartz. Like other varieties of macrocrystalline quartz, amethyst has transparent to translucent clarity and a vitreous luster. Cryptocrystalline varieties of quartz almost always occur with translucent to opaque clarity.

Amethyst Versus Citrine

Amethyst is the violet-colored sister stone of golden citrine quartz. Color-zoneametrine is the bicolored combination of both amethyst and citrine. The only difference between amethyst and citrine is the level of iron impurities in amethyst. When amethyst is heated at high temperatures of around 470ºC to 750ºC, iron impurities are reduced and can turn violet amethyst into golden 'heated' citrine. Lower grade amethyst stones are often heated to produce golden colored citrine stones. Heated citrine will typically appear more reddish when compared to unheated citrine.

Since purple is considered to be one of the royal colors, amethyst has a historical importance as an insignia of power. Fine amethysts are featured in the British Crown Jewels and they were also a favorite of Catherine the Great and Egyptian royalty. Amethyst also holds a high place in the ranks of the Christian church and was referred to as "the stone of bishops". The Greek word "amethystos" translates into "not drunken" and it was often worn as an amulet to protect against intoxication. Since amethyst was considered an antidote against drunkenness, many wine goblets were carved from amethyst stone. Still to this day, violet-purple amethyst is a symbol of sobriety.