Formula: SrSO4

Species: Sulfates

Colour: Colourless, shades of light blue, white, reddish, greenish, brownish, greyish; colourless or lightly tinted in transmitted light

Lustre: Vitreous, Pearly

Hardness: 3 – 3½

Specific Gravity: 3.96 – 3.98

Crystal System: Orthorhombic

Member of: Baryte Group. Baryte-Celestine Series. The strontium analogue of Baryte. By far the most common strontium mineral.

Name: Originally named fasriger schwerspath by Andreas Gotthelf Schütz in 1791. Renamed schwefelsaurer strontianite aus Pennsylvania by Martin Klaproth in 1797. Renamed by Abraham Gottlieb Werner in 1798 in German zoelestin from the Greek cœlestis for celestial, in allusion to the faint blue color of the original specimen. Renamed Schützit by Dietrich Ludwig Gustav Karsten in 1800. Although far superior celestine crystals were previously known from Sicily, they were thought to be barium-rich as the element strontium was not discovered until the late 1780s and not formally described until 1792.

Type Locality: Bell’s Mill, Bellwood, Blair Co., Pennsylvania – USA