I'm selling this as I received it as a gift but don't use it. It has the patent number PAT2007. I received it as a present with the explanation that it "has good effects on the body." It's a very beautiful necklace with small, shimmering natural stones layered together ^ ^ *** I'm not very knowledgeable about natural stones, but I think it might be tourmaline or fluorite. I'm not sure about the exact type of stone. Please judge from the images. #PowerStone #Tourmaline #NaturalStone #PTA2007v