1. 109 Peking University Jewelry Appraisal Center, upstairs of the wedding building, opposite to Xidan Shopping Mall in Xidan area.
2. Peking University Jewelry Appraisal Center (not for individuals) on the first floor of National Jewelry Quality Supervision and Inspection Center on the third floor of Ende Jewelry City in West Fourth District charges about 50 yuan.
3. China Capital Commercial Federation Testing Center, 6th Floor, National Inspection Center, 4th Floor, Wante Jewelry City, Xinjiekou.
4. The 9th floor of Tianya Antique City, north gate of Panjiayuan flea market in Panjiayuan area (or 10 floor has no accurate record).
There is also one on Gongmei Building behind Huapu Building on Chaoyangmen Chaowai Street.
In addition, basically every jewelry city will have a testing center.
Of course, you can go to a store that specializes in selling natural red corals and show your products to the store. They should all be happy to help you identify the authenticity.
Taobao is the most professional wholesaler of natural red coral in Taiwan Province and the best red coral in Bao Dao.