Black stone can bring an unexpected beauty to a piece of jewelry. It can also serve a number of different purposes for that piece, whether it's contrasting the rest of the stones, complimenting similar stones or just standing alone as a statement piece. Picking the perfect black stone is crucial to the jewelry-making process, but there are many different kinds of black stones to choose from.
Black Opal
Black opals, which can appear dark blue, green or brown, are by far the most rare and expensive of all opals. They're often used in jewelry as cabochons -- polished domed shapes -- and are usually found in pendants and as centerpieces to rings. Australia is the source of 97 percent of all opals, while just a few countries in Africa, South America and Eastern Europe are natural producers. In 2008, NASA added an unexpected opal source to this roster -- Mars.
Black Tourmaline
Unlike black opals, black tourmaline -- also known as schorl -- is the most common in the wide spectrum of tourmalines. In fact, 95 percent of all tourmalines in the world are black. The mineral's high iron content is credited for its rich, opaque color. Because tourmalines naturally form in long, narrow shapes, they're generally cut into facets and used in all types of jewelry, including necklaces, bracelets, rings and earrings.
Black Onyx
Onyx is the most traditional of all black stones and has been used in jewelry and ornamental design for many centuries. In ancient Rome, soldiers carried banded onyx engraved with images of their heroes for inspiration; during Queen Victoria's reign, onyx was used for cameo brooches; in the Art Deco period, onyx added contrast to ruby and quartz jewelry designs. In modern jewelry, onyx is shaped into beads and cabochons, and, like tourmaline, can be found in all forms of jewelry. Onyx continues to be used in cameos and intaglio carvings.
Black Diamonds
The black diamond, also known as carbonado, differs from traditional -- or white -- diamonds in many ways. Black diamonds are just as hard as white diamonds but endure stress better due to the structural difference between the two. White diamonds are made of solid crystal, while black diamonds are made of millions of conjoined crystals. Mostly found in only two countries -- Central African Republic and Brazil -- black diamonds are much more rare than other diamonds. Most black diamonds used in jewelry are lab-created whereby white diamonds are heated to create the black color. These lab-created diamonds are found in everything from rings and bracelets to necklaces and earrings.
Other Black Stones
Other black gemstones that can be found in jewelry design include jet, cassiterite, serendibite, black star diopside, obsidian, tektite, hematite and lodestone. Stones traditionally known for ranging in colors from red to violet also have black variations. These include black sapphires, black fluorites, black jaspers, black zirconias, black garnets, black spinels, black moonstones and black beryls, known as emeralds in the green form.