Each tumbled and polished gemstone is approximately 12-24 mm.   Listing is for 1 tumble.
 
Moonstone properties include:
Promotes  happy home & combats mood swings
Aids wisdom & insight
Increases creativity & passion
Soothes & calms the emotions & inner self
Helps combat cycles and repeated patterns
 
Chakra: Third Eye, Crown
Zodiac: Cancer
Element: Water
Planet: Moon