Pearls Certificate

how igl classifies and identifies pearls


IGL applies the same item identification and tracking procedures to all pearls, as it does for colored stones and diamonds. Each item is assigned a bar-coded label with a unique internal identification number that is used to track it throughout the process. And at every step, special inspection, care, and handling procedures ensure items are managed with the utmost care.
This is the first stop for any item submitted for pearl services. Pearls are counted by hand and then weighed with an electronic micro-balance that captures the weight in grams (mounted or strung), carats (loose), or carats and grains (loose natural). Pearls are measured using special digital calipers.


Items are then transferred to the Identification Inventory Control department for distribution to trained and experienced gemologists for servicing. Once an item is received by an initial gemologist, its recorded weight and measurements are verified. The gemologist identifies pearl types, mollusks and any detectable treatments using the standard gemological testing and advanced testing equipment, including real-time x-radiography, UV-Vis reflectance spectroscopy and XRF. Real-time microradiography equipment is used to measure the nacre thickness of bead-cultured pearls if the nacre appears thin or when requested by the client.
The gemologist determines color and classifies the other fators under a controlled viewing and lighting environment, using a comprehensive set of pearl masters. The pearl master sets include a hue circle and various color grids to determine color, and type-specific master sets of strands to classify luster, surface and matching.
After that, the item is transferred to a second gemologist, who independently performs all necessary observations and testing. Depending on the identity and nature, the item may be examined by additional gemologists and research specialists.

igl’s 11 pearl value factors

1. mollusk
2. shape
3. size
4. body color
5. overtone
6. surface
7. luster
8. kind
9. origin
10. water
11. nacre

Smaple Pearls Certificate