IUPAC Name: Nickel sulfide
Molecular Formula: Ni₃S₂
Molecular Weight: 240.25g/mol
Density: 5.8 g/mL at 25 °C(lit.) 
EINECS: 234-829-6 
Transport information: UN 3077 9/PG 3
Properties: opaque trigonal - trapezhedral crystal with light bronze streak
Color: pale bronze 
Freely Rotating Bonds: 0
Polar Surface Area: 32.09 Å² 
Air and Water Reactions: Nickel sulfide  -150 MESH 99.7% is sensitive to prolonged exposure to air. Insoluble in water.
The Cas Register Number of Heazlewoodite is 12035-71-1.The chemical synonyms of Heazlewoodite (CAS NO.12035-71-1) are Nickel sulfide  -150 mesh 99.7% ; Alpha-nickelsulfide(3:2)crystalline ; Heazlewoodite[qr] ; Nickelsesquisulfide ; Nickelsubsulfide ; Nickelsubsulphide The molecular structure of Heazlewoodite (CAS NO.12035-71-1) is.

It is known from few ultramafic intrusions within terrestrial rocks. The Honeymoon Well ultramafic intrusive, Western Australia is known to contain heazlewoodite-millerite sulfide assemblages within serpentinized olivine adcumulate dunite, formed from the metamorphic process.

  Heazlewoodite (CAS NO.12035-71-1)  can be used in producing of Sulphur and Nickel .

It is formed within terrestrial rocks by metamorphism of peridotite and dunite via a process of nucleation and only formed via metamorphic exsolution of sulfur from the lattice of metamorphic olivine.

IARC Cancer Review: Animal Sufficient Evidence IMEMDT    IARC Monographs on the Evaluation of Carcinogenic Risk of Chemicals to Man . 49 , 1990,p. 257.(World Health Organization, Internation Agency for Research on Cancer,Lyon, France.: ) (Single copies can be ordered from WHO Publications Centre U.S.A., 49 Sheridan Avenue, Albany, NY 12210) .

Confirmed carcinogen. When heated to decomposition it emits toxic vapors of SO_x and Ni.
Hazard Codes: T,N
Risk Statements: 49-43-51/53 
R49: May cause cancer by inhalation. 
R43: May cause sensitization by skin contact. 
R51/53: Toxic to aquatic organisms, may cause long-term adverse effects in the aquatic environment.
Safety Statements: 53-45-61 
S53: Avoid exposure - obtain special instructions before use. 
S45: In case of accident or if you feel unwell, seek medical advice immediately (show the label whenever possible.) 
S61: Avoid release to the environment. Refer to special instructions / safety data sheets.

 Heazlewoodite (CAS NO.12035-71-1) is a rare sulfur-poor nickel sulfide mineral found in serpentinitized dunite.It has a hardness of 4, a specific gravity of 5.82.