Amber

Amethyst

Aquamarine

Aragonite

Aventurine

Azurite

Carnelian

Citrine

Connemara Marble

Emerald

Fluorite

Garnet

Hemetite

Imperial Topaz

Iolite

Jade

Jasper

Kunzite

Labradorite

Lapis lazuli

Leopardskin

Malachite

Moldavite

Moonstone

Moss agate

Peridot

Quartz Crystal

Rose Quartz

Ruby

Sapphire

Serpentine

Snowflake Obsidian

Sodalite

Tourmaline

Turquoise

Zircon

Topaz

Topaz is one of the hardest minerals, and is the hardest silicate mineral found in nature. A silicate of aluminum, topaz contains about 20 percent water and fluorine. The relative proportions of these impurities are responsible for the color of the stones. Crystals with more water are yellow to brown, while those with more fluorine are typically blue or colorless. The most valuable is a rich orange-yellow, resembling the color of sherry wine known as Imperial Topaz, indeed some scholars trace the origin of the word topaz to the ancient Sanskrit word for fire, or tapas, a reference to its fiery orange color.
These colors can change when exposed to sunlight and/or heat. Brown topaz can be bleached by sunlight and yellow topaz turns pink to purple-red when exposed to moderate heat. . Nearly all the pink topaz sold as jewelry has been heat-treated. "Burnt topaz" is often known as Brazilian ruby, as is the very rare, natural red topaz.

Natural blue topaz, which is treated to create the bright blue variety, is found in Brazil, Sri Lanka, Nigeria, and China. In early 1998, yet another new type of radiation-enhanced topaz made its appearance, the surface-enhanced topaz. This variety of topaz has a color that is confined to a microscopically thin layer at and just below the surface, with colors described as blue to greenish-blue or emerald green.

Colorless topaz, when brilliant-cut, has often been mistaken for diamond. For years, the Braganza, a famous stone of 1640 carats set in the Portuguese crown, was thought to be the second largest diamond ever discovered. It is now believed to be a colorless topaz.

The ancient Greeks believed that the crystal had the power to increase a person's strength and make its wearer invisible in times of emergency and the gem's mystical curative powers waxed and waned with the phases of the moon. .Topaz was also said to change color in the presence of poisoned food or drink.