It isn't always what it seems....

I have spent a fair amount of time recently working on my equipment, and I decided that a piece of "rough" limestone was an excellent sample to look at.  Since the BPC had a "share" for "what is it" photos I took the following (shown as a 3D anaglyph).  The width in the top photo is about 1/2 inch.

My dear wife took one look and suggested this as a better "what is it"--I have to agree that she has a good eye!

The limestone is on the right, mixed breakfast cereal on the left.