Quartz var. Amethyst

Unknown Owner

A quite stunning small cabinet specimen of Gahnite with Quartz and Pyrite from the Silberberg mine, close to Bodenmais in the Regen District of Lower Bavaria, Germany. Gahnite is a member of the Spinel Group and occurs as fine octahedral crystals in this rare specimen. The Silberberg mine is an ancient mine dating back to at least 1436 which exploited a iron sulphide deposit in a Cordierite-Garnet gneiss. Octahedral, opaque, jet-black Gahnite crystals up to 1.8 cm on edge are richly embedded in a matrix of massive milky Quartz containing blocks of granular Pyrite to 2.5 cm. The Gahnite crystals have a sub-metallic lustre with crackled faces. Many fractures crossing some of the prisms are filled with recrystallised Quartz. This rare and fine example of well crystallised Gahnite from Silberberg comes with a U.S. National Museum (Division of Mineralogy) label and an old handwritten label.