• Grows in orthohombic patterns 
  • Primarily blue, light to dark, but also forms in brown, colorless, green, grey, and light red crystals
  • 3-3.5 hardness
  • Brittle to conchoidal (seashell like) fracture
  • White streak
  • 4.0 specific gravity
  • Vitreous (glassy) luster

Celestine, also known as celestite, is a strontium sulfate with the chemical formula Sr(SO4). It’s named for the Latin word for heavenly, or celestial, coelestis. This is the rock that inspired my url, coelestisinfesus, by the way. Celestine is generally found with sedimentary rocks, typically gypsum, anhydite, and halite. It can also be found in geodes, as pictured above, The largest geode in the world is composed of celestine, and is 35 feet in diameter at its largest point. Celestine crystals usually grow in crystals more than 4 inches in length, but have been known to grow to more than 30 inches. Celestine is generally considered too soft to cut, which is why very little jewelry is made out of it. The few pieces that are cut are more expensive. Personally, I think this is a huge loss, because celestine is great and it’d be like wearing the sky. 

(None of the above pictures are mine)