Presentation :
Names) :
Obsidian / Volcanic Glass: Mahogany or Magahony.
Etymology:
Obsidian: Named after the Roman Obsius, who is believed to have discovered this stone in...
Presentation :
Etymology: from the Greek apo, far from, and phyllos, leaf, with reference to its exfoliation when heated.
Chemical formula : KCa 4 Si 8 O 20 (F,OH).8H 2 O
Crysta...
