Description

Large floating quartz crystal, recrystallized on all sides and colored by fine hematite inclusions. This mineral comes from the Bierghes quarry, located in Walloon Brabant, 30 km from Brussels. These quarries have been exploiting “Porphyry”, a plutonic magmatic rock, since the 18th century, for the production of ballast due to its good mechanical properties. The operation encountered pockets of very clear quartz crystals reminiscent of Alpine facies (developed prism, Dauphiné habitus). These quartz crystals date back to the Hercynian orogeny, i.e. 300 million years ago. The magazine “Le Règne Minéral” devoted an article to this famous mineralogical deposit.

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