Hawleyite

Hawleyite is a rare sulfide mineral in the sphalerite group, dimorphous and easily confused with greenockite. Chemically, it is a cadmium sulfide, and occurs as a bright yellow coating on sphalerite or siderite in vugs, deposited by meteoric waters. It was discovered in 1955 and named in honour of mineralogist James Edwin Hawley, a professor at Queen's University in Ontario, Canada.
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General Information:
 Chemical Formula:
CdS
 Composition:
(Molecular Weight = 144.48 gm)
Cadmium 77.81 % Cd
Sulfur 22.19 % S 
 Empirical Formula:
CdS
Physical Properties:
 Cleavage:
None
 Color:
light yellow.
 Density:
4.87
 Diaphaniety:
Opaque
 Hardness:
2.5-3 - Finger Nail-Calcite
 Luster:
Metallic
 Streak:
light yellow
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