Mineralpedia Details for Ullmannite
The discoverer of the mineral, Johan Christoph Ullmann, a German chemist and mineralogist, is the namesake for Ullmannite. Relatively common and widespread, Ullmannite is found with nickel-bearing minerals in hydrothermal veins.
Ref. Handbook of Mineralogy, Anthony et al (1995) and MSA at http://www.handbookofmineralogy.org/pdfs/ullmannite.pdf
Ullmannite from Monte Narba, Sarrabus, Sardinia, Italy
Silvery, cubic crystals to 5mm.
Ullmannite from Siegen, Westphalia, Germany
Grey silvery rich mass.