Our Galaxy Opals are sourced from an opal mine in Magdalena, Mexico, where our supplier is local to the area. The opal part of the cabochon is 100% authentic – some colour varieties are natural and some of the brighter colours are enhanced with a dye for extra flair. (This is noted on each item listing). The manmade part which surrounds the opal is a rhyolite volcanic matrix, which is manipulated to give the opal more symmetry. The flash and glitter of the stone is completely natural.