These were mined prior to 1850. This beautiful and historic specimen is composed of roseate crystals of radiating covellite that are partially coated by a druse of secondary pyrite. The iridescent, neon blue color along with the lustrous pyrite and rosette form makes this a superb specimen with lots of color! Brilliant peacock-blue with plum coloration highlight this Italian Covellite, in contrast to covellites from other locales. The luster is superb, and the iridescence is visually transfixing. The platy, flat-lying blades range up to 5 cm across. Covellite is considered one of the 'holy grails' by Italian collectors, and the Calabona mine produced very few of them. The pics speak for themselves - this is excellent and aesthetic. And I have to say that a Butte piece of this caliber, would sell for even more money though it is more common material (with more people systematically looking for one). This specimen is GORGEOUS, BETTER In PERSON! It is hefty at 460 grams.