NGTC National Inspection Certificate is a diamond certificate issued by the National Jewelry and Jade Quality Supervision and Inspection Center (hereinafter referred to as the Inspection Center). NGTC Inspection Center is the authoritative organization for jewelry and jade inspection in China. Provide entrusted inspection services to the society and undertake many tasks such as national supervision and inspection, arbitration inspection, import and export commodity inspection and formulation and revision of relevant national standards in the jewelry and jade market. NGTC Testing Center has three testing centers in Shanghai, Beijing and Shenzhen.