This is a well-finished, double-sided green Heena Jasper from India. Kind of an olive green, the color is also known as "Mehendi".
It's good for those interested in collecting the many forms of agate, jasper, or sometimes other minerals. Heena Jasper is actually a hard serpentine marble material.
Although this is a cab, you can also glue on "bails", or have the piece drilled to accept a pinch bail. Either approach will let you turn this sample into a fine pendant.