http://inspire.ec.europa.eu/codelist/CommodityCodeValue/spinelGemstoneINSPIRE Registry teamJRC-INSPIRE-SUPPORT@ec.europa.euhttp://inspire.ec.europa.eu/registry2015-08-18 18:10 PM CEST2015-08-18 18:10 PM CESTspinel-gemstoneThe Spinel Group contains over twenty members, but only a few are considered common. They are a group of oxides that have very similar structures. Named after their sole gemstone representative, spinel, this is an important group of minerals. - http://www.galleries.com/Spinel_Group