This dinosaur bone I cut and polished is quite interesting. I am not exactly sure what the white matrix on the bone is unless it agatized or formed some sort of quartz which it reminds me of. There is a lot of color in this dinosaur cabochon to include browns, white, rust orange, burgundy, and black. There is some small pitting, in one area, on the surface of the bone which you cannot see unless you hold up to the light. I have reduced the price accordingly, but I do not feel it takes away from the beauty of this cabochon at all. It measures 30 x 23 mm and is 4 mm thick.