I am SO glad I bought these!  I was kind of on the fence because I liked another set more that was out of stock, but I am really glad I got these.  In fact, I'd like to get more.  They are so classy.  The surface is definitely stone and some of the beautiful natural striations shows through.  The bottom of the coasters is protected by padding so they won't mess up your table.  The gold is a nice touch and looks expensive.  This was a great buy.