摩氏硬度
As with the coin cabinet collection, the mineralogical collection traces its origin to the private collection of Archduke Johann, which encompassed several thousand pieces at that time. Today the inventory has grown to about 80,000 specimens. The collection presents minerals from across the world as well as a Styrian regional collection. The mineralogy department of the Joanneum was where Friedrich Mohs developed the Mohs scale of mineral hardness which remains authoritative. He was the first curator of the Joanneum.