Amethyst is a violet variety of crystallized quartz. Like all quartz, the hardness of amethyst on the Moh’s scale of hardness is 7. Its chemical formula is SiO2. Amethyst is the birthstone for the month of February.
Aquamarine, the semi precious stone, is the sea-green gem variety of Beryl. Aquamarine is a beryl with a hexagonal crystal structure and a chemical formula of Be3Al2(SiO3)6, a beryllium aluminium silicate mineral. The color is aquamarine is from light blue, blue-green to dark blue.
Citrine is a amber colored variety of quartz. The colors of citrine can range from sunny yellow to vibrant orange to golden brown. Like all quartz, the hardness of citrine is 7 (Moh Hardness). Its chemical formula is SiO2. Most citrine comes from Brazil. They can also be found in in the Ural Mountains of Russia, in Dauphine, France and in Madagascar. The enhancement of citrine is by heat in order to alter color and clarity.
Jade
Rubellite is a outstanding beautiful gemstone from the colourful family of the tourmalines. Valued for its ruby color, it exhibits a range of color from pink to red. The rubellite's Moh Hardness is 7-7.5. Rubellite can be found in Madagascar, North America, Brazil, Myanmar (Burma), Africa, Siberia, Australia, Sri Lanka (Ceylon).
