Guji 7 janvier 2017 Ruby & Sapphire: A Gemologist’s Guide by Richard W. Hughes with Wimon Manorotkul and E. Billie Hughes. http://www.lotusgemology.com/index.php/2-uncategorised/328-ruby-sapphire-a-gemologist-s-guide-order-page ← CNN – How sapphires are changing Madagascar’s fortunes Mémento spécial Mada 2017 →
