I checked it for you, and there is no refractive index and density on it. Maybe the "Jiangsu Gold and Jewelry Testing Center" you identified doesn't have this service. Because its name is "Gold Jewelry", it may be a testing institution that mainly detects metals, and does gem business by the way. After all, it is now required to establish a comprehensive ~

There is nothing wrong with the certificate. You can measure it on a more accurate scale. If there is no problem with the quality, it is rarely a fake.

If you are still not at ease, you can go to a special jewelry appraisal institution to test it-"National Jewelry and Jade Quality Supervision and Inspection Center", which is the most authoritative jewelry and jade testing institution in China.