- Cabinet, 14.5 x 7.1 x 4.8 cm
- Musaloni Mine, Sarrabus, Sardinia, Italy
Ullmanite is a rare nickel, antimony, sulfosalt, that forms in the isometric system. This matrix piece is studded with DOZENS of highly lustrous, metallic gray cubes that reach .6 cm across. In fact, an in-depth look at these crystals will reveal that many of them form penetration twins, just like fluorite. This is one of the richest such specimens I have ever seen for sale or know to exist, and it is an incredibly important example from this classic locality. Ullmanite, in good crystals, occurs very rarely elsewhere and the best are known from here. This piece was one of the best found in recent re-working of old mine adits by some intrepid Italian friends.