Gemstones commonly used for brooches were emeralds, diamonds, rubies, amethyst and topaz. Some common semi-precious gemstones including chalcedony, opal, quartz, turquoise, jade, amethyst, petrified wood, and topaz. Common colored varieties include citrine, rose quartz, amethyst, smoky quartz, milky quartz, and others. The steering wheel features a removable brooch set with amethyst, topaz, and citrine stones. Other names for green quartz are vermarine, greened amethyst, or lime citrine. Sometimes amethyst and citrine are found growing in the same crystal. Semi-precious stones like carnelian and amethyst are also used. Although citrine occurs naturally, the majority is the result of heat-treating amethyst or smoky quartz. Ruby is one of the traditional cardinal gems, together with amethyst, sapphire, emerald, and diamond. Semiprecious stones such as carnelian and amethyst may be used, as well. Most geodes contain clear quartz crystals, while others have purple amethyst crystals. Red Diamond, Silky White and Amethyst Black. Jewels are ranked in the order of amethyst, ruby, emerald, and diamond. An example is amethyst, which is a purple variety of quartz. Crystals are found throughout much of the Alpine region such as cinnabar, amethyst, and quartz.