Gem- and jewelry-themed tours and excursions mix treasure hunting with adventure and cultural experiences.
Last year, when Roberto Ruiz visited the Carbonera mine in Querétaro, Mexico, he cracked open a grapefruit-size piece of rhyolite with a hammer. When he looked inside, “it was like finding a fire fossil,” he said during a recent phone interview from his home in San Antonio. Inside was an orangey-red fire opal that he likened to a flame, forever preserved in the sphere of igneous rock.
Mr. Ruiz and his wife, Erika Rodriguez, are among the few people who have traveled to the mine, a desolate spot located in Carbonera in central Mexico, a destination that’s well off the beaten tourist track, some 20 miles from the nearest city.