The diamond ring in Tianjin can only be tested by Sinosteel Tianjin Geological Research Institute. The diamond rings I bought last time were all tested there, once about 100-200 yuan. It belongs to China sinosteel Company. Mainly engaged in mineral geological exploration and scientific research, scientific research and development of mineral processing technology, commodity inspection and nondestructive testing of gold ornaments for import and export mineral products, teaching, scientific research and identification of jewelry and jade, processing and sales of jewelry, etc. Have a reasonable team of technicians and perfect R&D facilities. Address: No.42 Youyi Road, Hexi District, Tianjin