CMA doesn't mean appraisal certificate, but certification body. Appraisal institutions that can do jewelry appraisal in China must obtain CMA certification before they can issue appraisal certificates.
Generally, there is no problem with the identification certificate with CMA mark.
CMA, this is the national measurement certification mark. According to the National Metrology Law of People's Republic of China (PRC), in order to ensure the accuracy and fairness of the test data, any quality testing institution that issues a notarized test report to the society must obtain the qualification of "Metrology Certification", otherwise it is illegal. Metrological certification is divided into "national" level and "provincial" level, which are applicable to the national quality supervision and testing center and the provincial quality supervision and testing center respectively. "Metrology certification qualification" shall be supervised and managed by the national and provincial quality supervision, inspection and quarantine bureaus or provincial technical supervision departments respectively. The qualification of metrological certification is different from that of laboratory accreditation. In fact, it is authorized by the government and only applies to national and provincial quality supervision and testing institutions under the government and industry departments. As a testing organization jointly established by the former Ministry of Electronic Industry, the State Commodity Inspection Bureau and the Shenzhen Municipal Government, Shenzhen Electronic Product Quality Testing Center obtained the national metrology certification in 2004, with the certificate number: (2004) Qizi (H2402), and the scope of recognition is the same as CNAL.