Never worn opal charm on faux gold chain necklace / costume jewelry

New never worn opal pendant necklace. No tags but will come in small plastic original gift box. Received as a gift from Australia. I believe this is an authentic opal gemstone. The opal has lovely iridescent sparkle and appears to change colors depending on the light. Super cute. The pendant is mounted and also strung from a gold colored chain. I believe this chain is just gold colored metal and not gold-filled. I would characterize this as costume jewelry and would be perfect for a young girl or teen. Since it is not real gold I would not wear this is the shower, etc. The pendant measures 5/8th inch long x 3/8th inch wide. 17 inch chain.