Pyrolusite is an important industrial ore of manganese easy to mine and easy to crush and turn into industrial components. Specimens simply do not form often or well in good sized crystals. This is an aesthetic 1.7 x 3.5 x 1.0 lustrous prismatic fan of terminated crystals that makes for a fine thumbnail example of a crystallized rarity not often seen in collections. It fits diagonally in a TN box - although vertically, you'd have to call it a small miniature.