I don’t know what this is. 
Got it in a bucket of scrap stuff from Frank. Was broken chunk from what had been a large slab.
It was probably 3/4” thick and maybe 2”x 3” 
Pretty much all 90 degree angles.
It worked beautiful. Except one little spot. I sure would’ve liked to have the original slab. 
I didn’t finish it up yet. 
I’m still trying to decide if I should use it or maybe make a necklace.
I actually have never made a necklace 
Bjrogg