Honessite Locality: Halls Gap , Lincoln County, Kentucky , USA ( Locality at mindat.org ) Size: 6.2 x 6.1 x 2.5 cm. Metallic, brilliant nickel-green honessite crystals richly fill a 3 cm vug in this impressive matrix specimen from a now closed locality. Honessite is much rarer than its close-relative millerite. Ex. Martin Zinn Collection. — Photo: Robert M. Lavinsky · CC BY-SA 3.0
Honessite
Honessite is an IMA-recognized mineral species in the sulfate class, with the chemical formula (Ni₁₋ₓFe³⁺ₓ)(SO₄)ₓ/₂(OH)₂·nH₂O (x < 0.5, n < 3x/2).
It crystallizes in the hexagonal crystal system. It is a member of the Woodwardite, Hydrotalcite structural group.
IMA symbol Hon, IMA status: approved, named in 1956.
A rare oxidation product of nickel sulfide minerals.
It is found associated with Millerite, violarite, bravoite (Linden, Wisconsin, USA); reevesite, hydrohonessite, theophrastite (Unst, Scotland).
The mineral was named to honor Professor Arthur Pharoah Honess (1887–1942), American mineralogist, Pennsylvania State University, State College, Pennsylvania, USA.