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Calcium fluoride or
fluorite (CaF 2)
Fluorite is a mineral of the halogenides
class. It is not only a popular
gem, but also an important raw material
for the production of hydrofluoric
acid, fluorine and fluxing agents
(e.g. for the manufacture of aluminum)
and for the etching of glass.
Clear crystals are used as lens elements
for optical instruments. Nowadays,
artificially produced fluorite is
used in optics. The name fluorite comes
from the Latin word fluere (to
flow) and resulted from the use of
the mineral as a fluxing agent in the
extraction of metals. Fluorite displays
the colors purple, blue, green, yellow,
colorless, brown, pink, black and reddish
orange. At the end of the 19 th
century Ernst Abbe was the first person
to use natural fluorite crystals in
the construction of microscope objective
lenses in order to enhance
chromatic correction.
Oltscheren mountain
pasture (1623 m)
Hut no. 86 with the inscription “B
1873 H*: edifice on a solid foundation,
with a kitchen-cum-living room
since 1996; saddle roof with …,
three-room living area facing NE on
the first floor (two rooms in the
front, behind them a now unused
kitchen and behind this a store and
barn. Beside these a milking installation
with 5 stands. The hut belonged
to the Zeiss Works in Jena during
the period when the company was
mining for fluorite.
Innovation 15, Carl Zeiss AG, 2005
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Fig. 10:
The Alpine house in Bielen
(Bühlen) on the Oltscheren
Alps in 1889. Ernst Abbe can
be easily recognized in the
enlarged section produced
by Trinkler in 1930 using the
best Carl Zeiss copying
lenses available at that time.
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