An amethyst is a mineral gemstone that comes from quartz. It is usually transparent. It is valued because of its violet colour. Even though it is a form of quartz, it has more iron oxide (FeO) than any other kind of quartz. Because of this, some experts think that its colour comes from the iron in it. Heating the amethyst either takes away its colour or changes it to a yellow hue. Amethysts are found in Brazil, Uruguay, Canada (Ontario) and America (North Carolina). The rock amethyst is the birthstone of the month February. In the Mohs scale, it has a hardness of seven.