Inner diameter 17mm. It sparkles with fine pyrite (o^^o) There are also beads with rainbows, which are beautiful. Meaning and effects as a power stone: It is known as a power stone that combines the meanings of pyrite and fluorite. Fusion of intelligence and action: Fluorite, which clarifies thinking (also known as the "stone of genius"), and pyrite, which brings out positivity, are combined, and it is believed to have both clear thinking and the ability to take action towards self-realization. Evil warding and protection: Pyrite has long been called a "guardian deity" and is said to have a powerful effect of warding off evil and disasters. Good luck and prosperity: It is also said to bring good luck and prosperity to the wearer. Enhancement of concentration and creativity: It is also popular as a charm for those who want to improve their concentration and creativity in their studies and work. #NaturalStone #Pyrite #Fluorite