Pleonaste is an opaque, usually
black, variety of Spinel containing iron.
It may also be very dark blue or very dark green but
is gernerally considered to be black and is often referred
to as "black Spinel". Pleonaste is an intermediate variety of the Hercynite-Spinel Series.
It is essentially an iron-rich Spinel or a magnesium-rich Hercynite.
Pleonaste is similar to another Spinel variety
called Ceylonite, named for the island of Ceylon where
it was discovered. The two varieties differ in that
Ceylonite is a ferroan Spinel with little or no ferric iron and
Pleonaste is distinguished chemically by its higher iron
was first cited in the first edition of René Just Haüy's
Crystallography in 1801 when he substituted
the name Pleonaste for the name Ceylanite of Delamétherie.
Pleonaste from the Greek word for abundant referring to its numerous crystal forms.
René Just Haüy (1743-1822) was a French mineralogist
and is often referred to as the "Father of Modern Crystallography."
The mineral Haüyne
was named to honor him. Ceylanite
was first cited by Jean-Claude Delamétherie in his Journal de Physique
in 1793. The name Ceylanite was later resurrected as
Ceylonite, another variety of Spinel as described above.
(also de La Métherie or de Lamétherie) (1743–1817) was a French naturalist, mineralogist, geologist and paleontologist. Numerous minerals
were first systematically named by Delamétherie and
later substituted by Haüy. Another example of Haüy's
name substitutions is the substitution of the name Epidote
for Thallite of Delamétherie.
critisism of Haüy is that he did not adhere to some
of the historical mineral naming rules. Most early mineralogists
recognized the system of naming which had made its appearance
during the time of the ancient Greeks and Romans out
of the genius of the Greek language. They almost uniformly
adopted the termination "ite" for new mineral
Abraham Werner is
credited with the naming of many minerals with the ite
termination such as Apatite, Aragonite, Augite, Chalcolite,
Cyanite (Kyanite), Graphite, Leucite, Prehnite, Torberite
and Witherite. Abraham Gottlob Werner (1749-1817) was
a professor of mining and mineralogy at the Freiberg Mining Academy. He
was an influential teacher and his ideas shaped early geological
thought. Wernerite was named to honor him.
D. Dana later stated in the American Journal of Science
and Arts in 1867: "The ancient origin of this
termination ite, its adoption for most of the
names in modern mineralogy, its distinctive character
and convenient application, make it evidently the true
basis for uniformity in the nomenclature of the science."
James Dwight Dana (1813-1895)
was an American geologist, mineralogist, volcanolorist
and zoologist. The mineral Danalite
was named to honor