Cantera opal is Mexico’s signature: fire opal still nested in its pale rhyolite matrix, cut as one piece so the volcanic host frames flashes of orange, pink and green. Querétaro and Jalisco are the classic mining states. Each cabochon is a one-off natural composition.GEMIC Institute certifies every cantera opal in our Siem Reap laboratory and films the exact stone for its listing. One-of-a-kind pieces with worldwide tracked delivery and a 30-day return window.