Beautiful, botryoidal, sky-blue allophane with a pearly luster and amorphous, pastel-green to tan allophane richly and showingly coats the top of the mica schist matrix on this old-time Austrian specimen. The ancient mines at Astentofern worked locally enriched sulphide impregnations in green slates. Comes with an expertly handwritten, faded label from an older collection. The collection this came out of was a museum stash dating to prior to World War I.