Lapis Solaris

As you can imagine, this quality was very attractive to alchemists and others who dabbled in mysterious arts. The stones turned out to be barite, or barium sulfate. When heated with carbon, the barium sulfate converted to more luminous barium sulfide. The discoverers of these rocks dubbed them lapis Solaris, or sun stone. Since then, many other fight-storing compounds have been discovered. One of these, calcium sulfide, is commonly used to create theatrical effects and luminous dials. 

Barium group Barium sulfate Calcite Fluorite Galena Sphalerite Witherite Bamtine Baryta Blanc fixe Bolognian spar, Cauk, Ceruse de Venise Heavy spar Lapis bononiensis Lapis Solaris Satin white Schwerspath Spath pesant Tyrol white... 

A variety of baryte (. v.) used as a source of material for pigment production. Terry (1893), in a discussion of Baryta white, for example, says at Bologna, a nodular variety is foimd, called Bologna stone, which is notable for its phosphorescent powers when heated . The Bolognese shoemaker Vincenzo Casciorolus (1602), who discovered phosphorescence in the mineral baryte, is undoubtedly the cause of this phrase being used although he himself appHed the term lapis Solaris. 

Burmester Krekel (1998) Deer et al. (1992) 502 Rutley (1988) 436 Lapis Solaris... 

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