Years ago I went all the way to Peru to look for Peruvian opal and had very little success. I found these beauties in Tucson. The green shade of opal is my favorite. I have strung this necklace with all the good stuff. Labradorite, amethyst, turquoise, carnelian, Gaspeite, sugilite, ruby, ancient coral, green turquoise and Thai silver. 16 inches with 2 inches of extender chain. I have added a pendant of 2000 year old fossilized walrus tusk and turquoise from Alaska.