Hoelite

Hoelite

Yellow acicular crystals of Hoelite (picture size: 10 mm)
General
Category Organic minerals
Formula
(repeating unit)
C14H8O2
Strunz classification 10.CA.15
Dana classification 50.4.2.1
Crystal symmetry Monoclinic prismatic
H-M symbol: (2/m)
Space group: P 21/a
Unit cell a = 15.81 Å, b = 3.967 Å,
c = 7.876 Å; β = 102.67°;
Z = 2
Identification
Color Yellow, yellowish green
Crystal habit Acicular clusters
Crystal system Monoclinic - pseudo-orthorhombic
Cleavage Good
Streak Light yellow
Diaphaneity Semitransparent
Specific gravity 1.42
Optical properties Biaxial (+)
Refractive index nα≈1.75, nβ≈1.75, nγ≈2.0
References [1][2]

Hoelite is a mineral, discovered in 1922 at Mt. Pyramide, Spitsbergen, Norway and named after Norwegian geologist Adolf Hoel (1879–1964). Its chemical formula is C14H8O2 (9,10-anthraquinone).[3][1]

It is a very rare organic mineral which occurs in coal fire environments in association with sal ammoniac and native sulfur.[1]

References

Wikimedia Commons has media related to Hoelite.