Kupferkies - Kupferkies natürliche Stücke (Peru)

I wasn't expecting the metallic luster to actually catch the light the way it does, especially on the rougher edges where the tarnish shows blues and greens. My chunk has a nice heft to it too, heavier than I figured for the size.

The iridescent tarnish on my piece shifts between blue and gold depending on how the light hits it, which I wasn't expecting from a raw mineral. Each chunk came a slightly different size, and the copper iron sulfide has a nice weight in the hand.

Didn't expect the metallic luster to actually shift color depending on the angle, it's way more striking in person than in photos. Each chunk is a decent size and the natural shapes make them look great lined up on my shelf.