Bunsenite is the naturally occurring form of nickel(II) oxide, NiO. It occurs as rare dark green crystal coatings. It crystallizes in the cubic crystal system and occurs as well formed cubic, octahedral and dodecahedral crystals. It is a member of the periclase group. It was first described in 1868 for a sample from a hydrothermal nickel-uranium v... Found on http://en.wikipedia.org/wiki/Bunsenite