Yellow acicular crystals of Hoelite (picture size: 10 mm) - Locality: Carolaschacht Mine, Freital near Dresden, Saxony, Germany — Photo: Thomas Witzke · CC BY-SA 3.0 de
Hoelite
Natural anthraquinone — an organic mineral discovered in 1922 on Spitsbergen's Mount Pyramide.
Intro adapted from Wikipedia (CC BY-SA).
Hoelite is an IMA-recognized mineral species in the organic mineral class, with the chemical formula C₁₄H₈O₂.
It crystallizes in the monoclinic crystal system (space group P2_1/a).
Key properties: Mohs hardness 1.43; specific gravity 1.467; refractive index 1.833; optically biaxial.
IMA symbol Hoe, grandfathered status — known before the IMA’s founding, named in 1922.
Very rare, in crusts around the surface vents of a burning coal deposit.
It is found associated with Sal ammoniac, sulfur.
The mineral was named to honor Adolf Hoel (1879-1964), leader of the discovery expedition to Spitsbergen during which the mineral was found.