Tectosilicate (framework silicate), feldspar group, dimorph of paracelsian
Specific gravity: 3.10 to 3.45
Hardness: 6 to 6½
Colour: Colourless, white, yellow
Celsian occurs in amphibolite grade metamorphic rocks
rich in manganese and barium.
It is associated with manganese-rich aegirine and biotite, paracelsian, jacobsite, hausmannite, rhodochrosite, rhodonite, rutile, hyalophane, baryte, cymrite, taramellite, quartz, zoisite, spessartine, dolomite and muscovite
At Broken Hill, New South Wales, Australia, celsian has been described from lenses and streaks in acid gneiss associated with plagioclase.
At the Benallt manganese mine at Rhiw, Wales, UK, celsian and paracelsian occur in a band in shale and sandstone associated with beds of manganese ore.
Common impurities: Fe,Mg,Ca,Na,K,F