Objective To establish X-ray diffraction (XRD) fingerprint profiles of Crassostrea hongkongensis and determine its calcium carbonate content. Methods A total of 16 batches of C. hongkongensis samples were analyzed by XRD to establish the fingerprint. Based on hierarchical clustering analysis (HCA) and orthogonal partial least squares-discriminant analysis (OPLS-DA), characteristic information for identification of Crassostrea Hongkongensis concha was screened with variable importance in projection (VIP) value > 1. The content of calcium carbonate in the samples was determined by EDTA complexometric titration. Results The XRD fingerprint of C. hongkongensis was established, and its phase structure belongs to calcite-type calcium carbonate, with 13 common peaks identified. The similarity of all 16 batches of samples was greater than 0.99. HCA divided the 16 batches into 3 categories, and the VIP values of OPLS-DA showed that 5 diffraction angles made great contributions, which were 47.41°, 65.51°, 61.28°, 47.04° and 57.34° respectively. Among the 16 batches of samples, 15 batches had a calcium carbonate content exceeding 94%. Conclusion The established XRD fingerprint can be used for the identification and analysis of C. hongkongensis. Their quality meets the standards specified under Ostreae Concha recorded in the Pharmacopoeia of the People’s Republic of China (2025 edition), offering technical support for their development as traditional Chinese medicinal material and comprehensive utilization.

Crassostrea hongkongensis Dunker  /  X-ray diffraction  /  fingerprint  /  similarity  /  calcium carbonate