Post-slaughter Immediate Separation and Preservation of Whole Stones:
Complete, undamaged large bezoars (cattle gallstones) are valued significantly higher than fragments. Take multi-angle photos and record the animal’s ID number, slaughter time, and farm information. — Integrity has the greatest impact on value.

Preliminary Grading (can be done at the slaughterhouse):
Classify and separately pack into four categories: “whole / mostly whole / fragments / powder.” Avoid mixing, as it leads to depreciation in value.

Sample Testing:
For samples judged to be mid-to-high grade, we need to send them to laboratories capable of testing bilirubin and other components (HPLC, thin-layer chromatography). This allows us to offer higher prices based on composition. Relevant quality control methods can be found in literature and patents on Angong Niuhuang Wan and other traditional Chinese medicine QC documents (e.g., HPLC/TLC fingerprint analysis).

Avoid Contamination & Proper Dry Storage:
Rinse, air-dry in the shade, seal-pack. Vacuum-sealing or dry-packaging is preferred to maintain appearance and weight.

Transaction:
For high-value individual stones, first send a small sample batch for our authentication and sign a sample acceptance agreement.