Pendant is approx 2 inches. Includes 20 inch chain.  To request an 18 or 24 inch chain, simply leave a note for seller at checkout.  Black Obsidian is a very powerful and creative stone.  It increases self-control.  It forces facing up to one’s true self.  Releases imbalances and negative energies.  Black Obsidian is protective and provides support during change.  It repels negativity and disperses unloving thoughts.