Amethyst is a violet variety of quartz. Amethyst is a semi-precious stone that is often used in jewellery and its violet color is due to irradiation, impurities of iron and other transition metals.
A ruby is a pink to blood-red colored gemstone. All natural rubies have imperfections in them, including color impurities and inclusions of rutile needles.
Emerald is a gemstone colored green by trace amounts of chromium or sometimes vanadium. Most emeralds are oiled in order to fill in surface-reaching cracks so that clarity is enhanced.
Diamond is a solid form of the element carbon with its atoms arranged in a crystal structure. Diamond has the highest hardness and thermal conductivity of any natural material.
Sapphire is a precious gemstone with trace amounts of elements such as iron, titanium, chromium, vanadium, or magnesium. It is typically blue, but natural "fancy" sapphires also occur in yellow, purple, orange, and green colors.
Topaz is a silicate mineral of aluminium and fluorine. It is used as a gemstone in jewelry and other adornments. Common topaz in its natural state is colorless but can be made pale blue, golden brown to yellow orange.
Garnets are a group of silicate minerals that have been used since the Bronze Age as gemstones and abrasives. Garnet species are found in every colour, with reddish shades most common.
A pearl is a hard, glistening object produced within the soft tissue of a living shelled mollusk or another animal. Pearls have been harvested and cultivated primarily for use in jewellery.