u/Public-Specific8732

Copper 62%, titanium 1%, iron 25%, aluminum 5%, silver 2%, tin 3%, nickel 5%
Extremely hard, including an extremely hard oxide layer I had to grind through, and it ate through a brand new belt just to get that flat surface. I just wanted to see some dendrite crystals form and the result is this. Any ideas why it’s so hard to grind?
Also it’s magnetic

I’ve heard it called gem bronze. Can’t figure out how they got the grains so small even in normal bronze the grains are much larger than this.

Dinichthys with iridescent pyrite and a nodule attached

Found in Kentucky in the Devonian shales, it’s a skull plate to the top of a dinichthys, a smaller cousin to the much larger dunkleosteus.