Copper Firebrick Cabochon - approx. 14 x 14 x 4.2 mm

Copper Firebrick Cabochon - approx. 14 x 14 x 4.2 mm

Reclaimed copper infused Firebrick from a copper mine/smelter in Michigan, USA, unbacked

Coin for size reference: US Dime (similar size as UK 5p)