What Is Black Stone or Rock?

Coal

• Coal is, as the U.S. Energy Information Administration notes, a nonrenewable energy source made up primarily of carbon and hydrocarbons. It is the most abundantly produced fossil fuel in the U.S. The shiny black stones we refer to as coal can sometimes be a dull, brownish-black color. Depending on the types and amounts of carbon the stones contain, they are divided into four primary ranks: anthracite, bituminous, sub-bituminous and lignite. Coal is a sedimentary rock formed from the heating and compression of buried plant matter over millions of years.

Gemstones

• Jet black onyx is typically the first gemstone that comes to mind when you think of black rocks, but there are many rocks used in the jewelry business that are predominately black. Specimens of agates, Chinese writing stones, ammonites, hematites (also known as "Alaska's black diamond), sapphires and pearls have all been found in colors of charcoal gray, slate and black. Wearing black gemstones is believed to protect the wearer's emotions, absorb negativity and represent fertility, according to Bernardine Fine Art Jewelry.

Basalt Rock

• Science Daily notes that basalt rock is a common black or dark gray volcanic stone that is the result of solidified and cooled liquid magma. Basalt rock is typically fine-grained, due to its quick-cooling nature once on the Earth's surface, though it may appear vesicular, frothy or porphyritic. Basalt volcanic rock makes up most of the crustal parts or the ocean's tectonic plates, and it is often found near coastlines.

The Black Stone

• The grand-daddy of black rocks has to be the Black Stone, an Islamic relic that is now mounted to the eastern corner of the Ka'bah -- the cube building in Mecca, Saudi Arabia, to which millions of Muslims make a pilgrimage each year. A number of differing theories exist on the Black Stone's origins, including that it is a meteorite; Adam and Eve took the rock from Eden; and that it was a gift from that archangel Gabriel. Traditionally, devouts attempt to kiss or touch the Black Stone in homage to Muhammad, who kissed it before his final pilgrimage.