Abstract
We conducted the following on the processing flaws (such as cracks or spots) that presumably had occurred because of inadequacies during the preliminary process.
1) We observed forms and structures of flaws under an optical microscope. We inferred that the flaws had been caused by stress due to the expanding and contracting of the nacreous layers.
2) Next, we did acceleration tests to determine how those processing flaws would develop and become more obvious with the passage of time.
3) We went on to apply expanding and contracting stress to flawless pearls, and tried to replicate the same sort of processing flaws.
