Unusual and attractive specimen with a look that is very unusual for Colorado! The doubly terminated Calcite (twinned) is nicely perched on contrasting Malachite. With magnification it can be seen that the Malachite is both on and in smaller Calcite crystals and has a silky texture. In very good condition as seen, I have only ever seen one other example from this locale, and this piece is larger and far more well-developed. It seems these were mostly found long ago and a few more collected in 1990. None since and the mine is fully defunct.