Authority. Gilde certificate is a jewelry appraisal certificate issued by American Guild Gemological Laboratory founded by American gemologist MrCharlesCarmona. The types of inspection reports that can be issued include advanced reports and routine inspection reports, which are suitable for all kinds of gems and meet the inspection requirements of all kinds of gems in the market. Dove blood red is the highest rating of ruby color in Gemology Laboratory of American Guild, which is authoritative. Guild certificate begins at 1980. It is a jewelry appraisal certificate issued by GUILD Gemological Laboratory in the United States, founded by American gemologist Charles Carmona.