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 Silver Blue Purple and brown. . We've taken a picture of a few pieces due to the nature of the item your going to get some variation from piece to piece. Please note no two stones are the same we are showing you the variation typically you get. Also note the sizes on these are a bit varying. Not made exactly to a particular spec. If you are mounting in a specific setting let us know and we will check sizes for you.