The Mineral celsian
Celsian is a very rare barium-rich member of the feldspar group. This mineral is named after Anders Celsius (1701-1744), a famous Swedish astronomer and scientist who proposed the Celsius temperature scale. Celsian forms a solid solution series with Orthoclase, and the intermediary member is known as Hyalophane. Although sometimes viewed as a variety of Celsian, Hyalophane is scientifically classified as a distinct mineral species.
Colorless, white, light yellow, brown, reddish-brown, blue, gray
6 - 6.5
Transparent to opaque
3.1 - 3.4
Vitreous to greasy
2,1 - basal ; 2,1 - prismatic ; 3,1 - pinacoidal. The cleavage angle is about 90º.
Conchoidal to uneven
Intermediary member of the Celsian-Orthoclase mineral series. Although sometimes
viewed as a variety of Celsian, Hyalophane is scientifically classified as a distinct
Celsian is a very rare mineral. Localities include the Benallt Mine, Rhiw, Wales; Jakobsberg, Nordmark, Sweden; Candoglia, Piedmont, Italy; the Kaso Mine, Kanuma, Japan; Broken Hill, New South Wales, Australia; and Franklin, Sussex Co., New Jersey. Hyalophane localities are the Zagradski Potok Mine, Busovaca, Bosnia and Herzegovina; and the Lengenbach Quarry, Im Feld, Binntal, Switzerland.
Common Mineral Associations
Quartz, Barite, Aragonite, Plagioclase
Distingushing Similar Minerals
Other Feldspars - Considerably lighter in weight.