The base is ground but the edges are not. Made of a great piece of Burlington, it has some completely translucent inclusions, and the whole piece looks great when backlit. The caliper hits 5/16", so it is well made and thin, just lacks the KILLER flaking of a Sloan. There is 1 corner that was broken off and glued back. Fairly clean break, but there is one small bit of material missing from the side with the sticker, right in the middle of the break. I tried to get a pic of the missing part, it's a VERY small amount. Larry Apodaca personally found this piece in Knox Co IL. Nice, large AUTHENTIC Artifact, despite the break. $175 now $130