Obsidian is igneous rock that forms when molten rock cools very rapidly. It is a form of volcanic glass with a smooth and uniform texture. Most obsidian is black, though it can also be found in various colors like brown, tan, green or the rarer yellow, red, orange, or blue. These colors are caused by trace elements in the rock.
Blue obsidian is very rare and is said to have properties that have found great use in many occult practices. It is said to aid divination, psychic, and psychometric practices. It is said to give you intuitive knowledge when you are traveling, and can help in creativity. Stimulation of visions is helped by this blue stone during the process of meditation. It is said to aid lingual skills and communication when used as in a necklace close to the throat.
As it looks very much like glass, it is often man-made and not genuine, as the true variety of the stone is very rare to find.