When sourcing pearl oysters, especially those containing pearls (vacuum-packed), you must evaluate the nacre thickness, luster, and surface cleanliness of the pearls inside. For the oysters themselves, ensure they are freshly harvested and properly preserved in a solution of alcohol and water to maintain tissue integrity. If purchasing for the purpose of 'pearl opening' events, the variety of pearl (e.g., Akoya, Freshwater, or Tahitian) and the guaranteed number of pearls per shell are critical technical specifications.