The use of fluorite for prisms and lenses was studied and promoted by Victor Schumann near the end of the 19th century. Naturally occurring fluorite crystals without optical defects were only large enough to produce microscope objectives.
The use of fluorite for prisms and lenses was studied and promoted by Victor Schumann near the end of the 19th century Naturally occurring fluorite crystals without optical defects were only large enough to produce microscope objectives