Authority. Shenzhen Zhong Da Jewelry Testing Co., Ltd. is a third-party jewelry appraisal agency. The staff inside are also very professional and have many years of experience and authority in jewelry appraisal. Their instruments are also very advanced and their equipment is very professional. Don't worry, there is a charge for jewelry appraisal there. After the fee is collected, you will be appraised and a detailed jewelry appraisal report will be provided.