is relate to one of the many amphibole-group mineral with formula
([ ],Na)(Na,Ca)2(Mg, Fe++)4Fe+++[Si8O22](OH)2 and hardness of 5-6.
Here is associate with jacobsite a dark brown manganese iron oxide mineral.
It comes from Langban,Filipstad,Värmland -Sweden.
Glowing in orange red on short wave due to calcite layers.
Size: 6.1x8x5.5 mm.
Weight: 2.98 ct.