This is a 1.8" polished, zebra jasper worry stone.
are smooth, polished stones, usually in the shape of an oval with a thumb-sized indentation. They are often used by people for relaxation or anxiety relief purposes, the the same way as some people use a fidget spinner. Typically the worry stones are 1 1/2 to 2" across. They are may also be referred to as palm stones, thumb stone, fidget stones, etc.
Zebra jasper is a type of jasper that features banding, streaks and spots of a brown-black mineral that formed in association with white-grey jasper (fine-grained opaque "chalcedony"). It is mined in Africa, Egypt, India and Russia and is known for its ability to handle a high polish, making it a perfect stone for tumbling and sculpting.