Krohnkite, uncommon and uncommonly attractive, is a hydrated sodium, copper sulfate, and good crystals ONLY came from the type locality of Chuquicamata, Chile. Krohnkite is particularly interesting: it is lustrous and translucent and has an intense, saturated, blue color. This small cab exhibits what is a classic habit for the species: lamellar growth of curved crystals in parallel bundles. Chuquicamata was a great mine, totally unique in its chemistry, that once produced an amazing suite of specimens. This is a significant, old example (purchased in 1961) of a great species. VERY rare on the market, today!