Jet is a product of fossilized wood. It is similar to coal, but harder and more durable. Jet actually comes from a particular tree, called Araucaria, which was a conifer tree from the Jurassic period, about 180 million years ago. When the trees died, some fell into swamps or rivers, broke up, and were carried out to sea. As the trunks and branches became wet, they sank to the bottom of the ocean. Eventually, pressure from the multiple layers of organisms and mud flattened the tree fragments together, and together with chemical changes, altered the wood to jet.
Jet has been mined since 1400 BC. In fact, pieces of jet have been found in prehistoric burial mounds. During the middle ages, carved pieces of jet were carried into battle to protect soldiers against spells. Travelers also carried pieces of jet carved into beetle shapes for protection. In Medieval times, polished pieces of jet were used as mirrors. In the Roman Catholic Church, black beads were the most popular color for rosaries and jet was often the stone of choice. Although set in jewelry since ancient times, it wasn't until 1861 that jet became popular as mourning jewelry, when Queen Victoria of England began wearing it after the death of her husband, Prince Albert. At that time, jet was carved into lockets, brooches, necklaces and earrings with all the popular Victorian motifs; flowers, ivy leaves, geometric patterns, and animals. Jet was even sewn into fabric, as beads in lacey trims. During this time, jet was exported all over Europe. Jet combs were very popular in Spain where they were used to hold up women's veils in church.
Jet has been used since Paleolithic times for various medicinal applications. Many cultures believed that the smoke released by burning jet was beneficial if inhaled. According to Pliny the Elder, powdered jet mixed with the marrow of a stag could heal snakebite. Jet was also powdered and mixed with beeswax, as this mixture was believed to shrink tumors. Mixed with wine, it was believed to alleviate toothaches and headaches. For centuries, jet has been believed to heal homesickness, strengthen wisdom, protect the wearer from violence, negative energy, bad health, and emotional struggles.
Jet is a black or dark brown opaque stone that can be tough to brittle, rating a 2 to 4 on the hardness scale. Like 
diamond, jet is made primarily of carbon. Some jet may contain pyrite inclusions, which have a brassy color and metallic luster. The fact that jet comes from wood is sometimes apparent in pieces that have a grain-like texture. Most jet however, is smooth. Jet feels warm to the touch and has been known as black 
amber as it can also become electrically charged if rubbed with a cloth, just like amber. Jet is usually found in carbon-rich beds in shale sheta. It occurs in tubers rather than in veins, and can be found washed up on the seashore. The best quality jet (considered the best because it takes such a good polish) comes from Whitby, Yorkshire. However jet can also be found worldwide, in England, France, Germany, Portugal, Russia, Poland, India, Spain, Turkey, and the United States.
