Celsian is an uncommon feldspar mineral, barium aluminosilicate, BaAl2Si2O8. It is an uncommon feldspar mineral, which was first discovered in 1895 in Imfeld Binnental, Switzerland. The mineral was named after the Swedish astronomer and natural scientist, A.Celsius. The mineral is named after Anders Celsius (1701–1744).
The mineral occurs in contact metamorphic rocks with significant barium content. Its crystal system is monoclinic, and it is white, yellow, or transparent in appearance. In pure form, it is transparent. Synthetic barium aluminosilicate is used as a ceramic in dental fillings and other applications.
- Category: Feldspar
- Formula: BaAl2Si2O8
- Crystal system: Monoclinic
- Crystal class: Prismatic (2/m) (same H-M symbol)
Celsian is either colorless, or occurs in yellow or white. It has perfect cleavage, transparent appearance, and non-fluorescent luminescence. It exhibits brittle fractures, white streak and vitreous luster. The mineral can appear as well-formed granular crystals.
The average density of celsian is 3.25 g/cm3, and its hardness ranges from 6 to 6.5
- Color: Colorless, white, yellow
- Crystal habit: Short prismatic to acicular crystals, massive
- Tenacity: Brittle
- Mohs scale hardness: 6 – 6.5
- Luster: Vitreous
- Diaphaneity: Transparent
- Specific gravity: 3.10 to 3.39
Celsian occurs in amphibolite-grade, regional, or contact metamorphic, Mn, Ba-rich rocks. It is of limited occurrence. Most of the barium feldspars are associated with exhalative hydrothermal processes and low-and medium-grade metamorphism (Moro and Cembranos and Fernandez, 2001). It is also associated with sedimentary and meta sedimentary rocks, manganese, ferromanganese and barite deposits.
It is closely associated with muscovite, dolomite, spessartine, zoisite, quartz, taramellite, cymrite, barite, hyalophane, rutile, rhodonite, rhodochrosite, hausmannite, jacobsite, paracelsian, manganoan biotite, and manganoan aegirine.
Celsian can be found in places like Wales, Zamora (Spain), Alaska, California, Sweden and Japan, also with hendricksite on the Franklin mines in New Jersey.