You are purchasing the stone in the photo. This stone is what we call a matrix stone. It is man made. I use this term to refer to stones created out of small pieces of natural material, then bound together with a very hard stone like compound. Something like a very hard resin. You see this type process used in fancy granite, marble or stone counter tops. They look very real and are tough. In this stone you have swirls of copper and aventurine held together by a turquoise colored matrix.  Please note no two stones are the same we are showing you the variation typically you get. Size is listed in the product title in millimeters (mm)