Gibbsite, an uncommon aluminum hydroxide, has replaced very large and three-dimensional prismatic crystals of crocoite, to 2.5 cm in length. The gibbsite exhibits a light tan color. Also associated with the pseudomorph is a druse of milky quartz. Overall, I would normally ignore this species and any pseudos of thin and scraggly crocoite as I have seen in the past. But, this robust example stood out when I saw it in an old collection at Munich.