genuine rainbow moonstone is set in a handmade 14k gold fill pendant The moonstone has nice flash of color The moonstone is 14 x 10mm and weights a little over 5.75 carats Comes with 14k gold fill 18 inch 1.3mm double rope chain and black velvet gift box Moonstone is the most famous member of the feldspar group. Technically, moonstone belongs to the orthoclase branch of the feldspar family and rainbow moonstone belongs to the labradorite branch. Moonstone's floating light that appears to emanate from within is known as adularescence. It is caused by structural anomalies within the stone, which refract or scatter incoming light. The size or thickness of these anomalies determines the color of the floating light. Moonstone is found in Sri Lanka, Myanmar, Madagascar, Brazil, Australia and India. The various colors only come from India and the other sources yield white moonstone. In India, rainbow moonstone is mined in the southwest and blue is mined at Bihar in the center of the country.