SILICATES; TECTOSILICATES; FELDSPAR GROUP · MONOCLINIC

Celsian

About

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.

Crystal Forms & Aggregates

Occurs as short tabular crystals and as long, slender prisms. Also occurs acicular, massive, and as crusts.

Complex Tests

Soluble in hydrochloric acid

Striking Features

Heaviness and localities

Environment

In barium-rich contact metamorphic rocks.

Varieties

✓ common · ✗ uncommon

Hyalophane— Intermediary member of the Celsian-Orthoclase mineral series. Although sometimes viewed as a variety of Celsian, Hyalophane is scientifically classified as a distinct mineral species.

Polymorphs

Paracelsian

Noteworthy Localities

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

Distinguishing Similar Minerals

Other Feldspars - Considerably lighter in weight.

Abouti

Crystal Forms & Aggregatesi

Complex Testsi

Striking Featuresi

Environmenti

Varietiesi