Hollandite–strontiomelane solid solutions coexisting with kanonaite and braunite in late quartz veins of the Stavelot Massif, Ardennes, Belgium

In a newly found type of quartz vein cross-cutting the famous "viridine"-bearing phyllites at Le Coreux, hollandite, ideally BaMn8O16, we discovered for the first time at this locality and in Belgium. Because the crystals contain up to 60 mol% of the Sr end member, this is also the second occurrence of strontiomelane.