Presentation :
Carnelian is a red variety of chalcedony, which is itself a cryptocrystalline variety of quartz. The formula of this mineral family is SiO2. Carnelian owes its color to hematit...
Presentation :
Carnelian is a red variety of chalcedony, which itself is a cryptocrystalline variety of quartz. The formula for this family of minerals is SiO2. Carnelian owes its color to he...
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 "barrus" = heavy, due to its high density.
Its genesis is mainly hydrothermal. It consists of barium, a crumb of lead, a hint of calcium and may co...
