Despite being miniature in size, the quality of this Italian Ullmannite is magnificent. Ullmannite is one of those sulphosalt species which is known from a significant, but not large number of places, but rarely in well-defined crystals. Mt. Narba mine in Sardinia, from where this wonderful piece comes, is one of just a small number of places where great crystals have been found, and is certainly regarded as the premier locality. Often, these crystals are encapsulated in white Calcite which is etched away to expose the cubic grey metallic crystals underneath. This absolute beauty is remarkable in several regards: firstly, the cubic crystals (which reach 4.5 mm on edge) are razor-sharp along their edges; then there is the twinning; their bright silvery colour and metallic lustre also stand out; finally, whereas some specimens can been seen to have been etched from Calcite, with its tell-tale smooth appearance, this piece does not show this texture, thus making it look more natural. There is slight damage to a couple of the Ullmannite crystals, but overall this is an exceptionally well-crystallized specimen, better than most Ullmannite seen in museums. It is from the superb systematic collection assembled by the brothers Martin and Michael Günther (1951-2007 & 1956-2021).
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