Genuine earth mined Opal. 12.6 x 9.8 x 8.3mm. If you are not sure how big this is , make certain you check on a measure marked in millimeters... the standard for measuring gems. October birthday A video of this gem is available on request.I only sell genuine earth mined gems, not man made. Please read the TERMS AND CONDITIONS page at least once as it applies to all listings. Any questions, please ask