Abundant, intersecting patches of turquoise blue, clusters of micaceous, <1mm crystals of develline are festooned on a mottled matrix. A large and significant specimen of this colorful calcium copper sulfate hydrate dating from the 19th Century with an old Chemische Fabrik und Mineralienhandlung label in ink using the moniker "Herrengrundite" for the locality at Herrengrund, Slovakia. Also accompanied by a William Metropolis label and said to be ex. Harvard. A great display piece and a historic specimen of large size, particularly for the price, as cabinet pieces are rare!.