How to Care for Bismuth?

An ornamental stone since antiquity, agate has been found in a variety of ancient Greek contexts, such as for Mycenaean jewelry and warriors' seal stones. Because it is hardy, often spectacularly colored, and polishes to a high shine, it has long been valued for decorative purposes. It is formed in alternating layers that produce the distinctive banding effect, of which there are many varieties worldwide.

A carbonate mineral, calcite has been a popular carving material since ancient times due to its softness; the Egyptians dedicated many artifacts carved from calcite to Bastet, the cat goddess. It may be either transparent or opaque, and perhaps tinted with other colors if tainted with traces of other substances.

This brilliantly violet variety of quartz is one of the most easily recognizable of gemstones. The amethyst is the birthstone of those born in February, and gets its name from Ancient Greek, in reference to a belief that this stone would protect its wearer from becoming too drunk.

Chert is a very hard sedimentary rock composed of tiny quarts crystals. Though it has few uses today, this material was invaluable to paleolithic humans. Hard and able to keep a sharp edge when knapped, chert was commonly used for arrowheads, knives, scrapers, and other tools. It also creates sparks when struck against steel, and so it was used as a firestarter, and later as a component in flintlock firearms.

Diamonds are incredible minerals that are composed solely of humble carbon. First mined in India as far back as 400 BC, they have only become popular during the last few centuries. Cut stones are prized for their brilliance, their dispersion (also known as "fire" - or the ability to convert white light into many different colors of light), and their hardness. Indeed, their extreme durability makes even specimens that are below gem-quality extremely useful in all manner of industrial, commercial, and medical settings, particularly when cutting or grinding is involved.

Black Agate is a type of microcrystalline quartz that is opaque and appears black or dark gray in color. However, the gemstone of black Agate in the market is usually created by suffusing chalcedony in a sugar solution and then treating with sulfuric acid, causing the stone's appearance to change to a black color. This process enhances the stone's appearance, making it very popular. It is commonly used as a Jet imitation.

This transparent stone has a complete lack of color or flaws. Its smoothness and clarity have made clear Quartz highly valued for use in jewelry or ornamental pieces. Modern-day crystal glassware derives its name from the clarity and fineness of this stone. Behind feldspar, this stone is the second most commonly found mineral in the crust of the Earth.

Carnelian Agate is a semi-precious stone prized for its beautiful yellow, orange, or amber bands combined with white. This banded form consists of Carnelian and Agate which are varieties of the mineral known as Chalcedony. Most of these polished stones are mined and produced in Botswana.