I know a little about obsidian. Crystal, white crystal and pink crystal can be worn on my left hand. Obsidian is generally recommended to be worn on the right hand, but at that time, many people did not know that obsidian could also be worn on the left hand. Wearing it on your left hand can ward off evil spirits and prevent foreign invasion.
It is generally recommended to wear it on the right hand because it can eliminate the negative energy of the human body.
So you can wear it on your left hand.