Jet, known also as gagate, is a carbon fossil, compact and very light. It is a lustrous black stone which has a hardness of 2.5-4 (quite soft) and a specific gravity of 1.30-1.35. This stone was named after the city of Gages in ancient Lykia.
Another name of jet is black amber. Jet was known in ancient Egypt, where it was used for making mirrors, in Greece and Rome they used it for cutting amulets, bracelets and rings. In Medieval times jet was popular as a talisman and a medicine for migraines, toothache, stomach pains and epilepsy, and it reached the height of its popularity during the Victorian period.
The history of jet in Russia began in the second part of the 19th century, when the big deposit was discovered in Siberia, near the city of Irkutsk. Since that time jet was widely used for carving, making all sorts of souvenirs. The main cathedral in Irkutsk was decorated with jet.
Even now people believe that jet has magical powers, it protects from nightmares and helps to overcome ones fears.