1) Monoclinic mineral
Found on
https://www.crosswordclues.com/clue/playfairite
Playfairite is a very rare sulfosalt mineral with chemical formula Pb16Sb18S43 in the monoclinic crystal system, named after the Scottish scientist and mathematician John Playfair. It was discovered in 1966 by the Canadian mineralogist John Leslie Jambor. Lead gray to black in colour, its lustre is metallic. Playfairite shows strong reflection ple...
Found on
http://en.wikipedia.org/wiki/Playfairite
No exact match found.
