Moonstone / Adular Cabochon 5.8g, India

Adular (moonstone) is a variety of the mineral orthoclas from the group of feldspars. Due to its composition - alternating layers of orthoclas and albite minerals - an optical phenomenon called "adularescence" (or Shiller) arises when light strikes, thanks to which Adular is so well known and highly valued.
It was named Adular after the place of its discovery, namely the Adul Mountains in Switzerland. But the most beautiful moonstones come from Sri Lanka, Tanzania and Madagascar.
Adular has been used in jewelry for millennia - records from ancient civilizations have been preserved. E.g. the ancient Greeks and Romans admired and worshiped the moonstone because they believed it came from the rays of the moon and associated it with the moon deities.
The so-called "cat's eye" effect is very rare with the adular.