These are man made synthetic glass/blue obsidian stones. However, they still have a very unique energy about them. This is a stone/glass that has been associated with spirit fire, genies, and guardian spirits that watch over us. It also has the influences from the mother Goddess, water, mystery. and ancestors. Also used to block negativity, enhance communication skills for presentations or other public speaking, and relaxation/meditation. These are the size of a quarter 3/4"- 1 1/4 and have been polished and tumbled.