Millerite
Chemical Formula	NiS
Species	Sulfides
Crystal System	Trigonal
Mohs Scale	3
Specific Gravity	5.3-5.5
Color	Pale brass-yellow, with an iridescent tarnish, and greenish-grey.
Streak	Greenish black
Luster	Metallic
Diaphaneity	Opaque
Cleavage	PerfectPerfect on and .
Fracture	Irregular/Uneven
Crystal Habit：Typically acicular (needle-like) often in radial sprays - also massive
Geological Setting：A low-temperature mineral which occurs in sulfidic limestones and dolostones, and as a late-forming mineral in nickel sulfide deposits.