Orange-yellow earthy Hawleyite coating, from Eureka County, Nevada. — Photo: Aram Dulyan · Public domain
Hawleyite
The cubic polymorph of cadmium sulfide — bright-yellow coatings on sphalerite, easily confused with greenockite.
Intro adapted from Wikipedia (CC BY-SA).
Hawleyite is an IMA-recognized mineral species in the sulfide class, with the chemical formula CdS.
It crystallizes in the cubic crystal system (space group F-43m). It is a member of the Sphalerite structural group.
Key properties: specific gravity 4.87.
IMA symbol Hwl, grandfathered status — known before the IMA’s founding, named in 1955.
Occurs as coatings on fine-grained sphalerite and siderite in vugs; probably of secondary origin, deposited from meteoric waters in vugs and along late fractures.
It is found associated with Sphalerite, siderite, greenockite.
The mineral was named to honor Professor James Edwin Hawley (1897–1965), Canadian mineralogist, Queen’s University, Kingston, Ontario, Canada.