CMA —— (China Metrology Certification) is a sign that the measurement certification of testing institutions is qualified, and the institutions with this sign are legal testing institutions. China Metrology Accreditation
CAL- (China Accredited Laboratory) is the symbol of testing and inspection institutions recognized by AQSIQ, and the institutions with this symbol are qualified to make arbitration inspection conclusions. National Accreditation Committee for Laboratories accredited by China's quality supervision and inspection institutions.
The symbol of Cnal (China Laboratory National Accreditation Committee) National Laboratory. This mark indicates that the inspection institution has passed the examination of China National Laboratory Accreditation Committee, and its inspection ability has reached the level of national laboratories (cma and cal only refer to the approval of provincial quality and technology management institutions).
CNAS China National Accreditation Committee for Conformity Assessment.
At the same time, it has three jewelry testing institutions: cma, cal and cnal. At present, there are National Jewellery and Jade Quality Supervision and Inspection Center, China Wuhan Jewellery and Jade Inspection Center, Shanghai Central Laboratory Jewel Inspection Center of Ministry of Geology and Mineral Resources, Yunnan Jewelry and Jade Ornaments Quality Supervision and Inspection Institute and other units.
Any of the above three marks is valid, especially the first mark cma, which is the basic requirement of national laws for testing and inspection institutions.