Overview
The Pearl Science Laboratory (PSL) is located in Tokyo, Japan. It is the premier organization recognized internationally as the certifier of Hanadama grade Akoya pearls. Hanadama is a Japanese term that was coined by the founder of the cultured Akoya pearling industry, Kokichi Mikimoto, which means spherical flower. Hanadama pearls comprise less than 0.01% of the Akoya pearls harvested annually. The Hanadama grade is still used to this day to designate the best quality Akoya saltwater pearls that can be found.

In order to have a strand of pearls certified as being Hanadama they are submitted to the PSL to undergo a series of tests on random pearls from the strand; such as soft x-rays, light spectro photometric reflectance, magnification, inner inspection by optical fiber, and the Aurora viewer. This allows the PSL to exactly measure nacre thickness, luster, surface imperfections, colour quality (etc.). At the end of this analysis if the strand has met the criteria for being of Hanadama grade a numbered certificate will be assigned to the strand of pearls by the PSL deeming it to be Hanadama grade.

The grading is not subjective, and must meet the following criteria:

Nacre depth is a minimum of 0.4mm per side (0.8mm total)
Teri-value (luster) analysis must be very strong
Surface imperfection (inclusion) grade must read very slight
Shape must be round

Select Pearls Hanadama strands also require the special appellation of being Aurora Hanadama pearls. This designation is proof that the pearls have exceptional lustre and have not been colour treated.

The PSL certificate does not allow for grading of no imperfections. This is because all pearls will have some degree of imperfection. Pearls are an organic gem, and though imperfections may be indistinguishable to the eye, they will still exist. For that reason the PSL does not allow for a 'perfectly flawless' grading.

PSL Certificate Image