Hawleyite is a rare sulfide mineral in the sphalerite group, dimorphous and easily confused with greenockite. Chemically, it is cadmium sulfide, and occurs as a bright yellow coating on sphalerite or siderite in vugs, deposited by meteoric water.^[4]

Hawleyite
Orange-yellow earthy coating
General
Category	Sulfide mineral
Formula (repeating unit)	CdS
IMA symbol	Hwl[1]
Strunz classification	2.CB.05a
Crystal system	Cubic
Crystal class	Hextetrahedral (43m) H-M symbol: (4 3m)
Space group	F43m
Unit cell	a = 5.818 Å; Z = 4
Structure
Jmol (3D)	Interactive image
Identification
Color	Bright yellow
Crystal habit	Powdery massive
Mohs scale hardness	2.5–3
Luster	Metallic
Streak	Light yellow
Diaphaneity	Translucent to opaque
Specific gravity	4.87
References	[2][3][4]

It was discovered in 1955 in the Hector-Calumet mine, Keno-Galena Hill area, Yukon Territory and named in honour of mineralogist James Edwin Hawley (1897–1965), a professor at Queen's University in Ontario, Canada.^[3][2]