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 each year. The Hanadama grade is still used to this day to designate the best quality Akoya saltwater pearls.

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

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

Nacre depth must not show to be less than 0.4mm (0.8mm when two sides are added)
Teri-value (lustre) analysis must be very strong
Surface imperfection (inclusion) grade must read very slight

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.

Although Hanadama is an industry term, it is not a grade designation in the A-AAA grading system. Technically speaking, a Hanadama rating is best described as a certified AAA strand. It is a benchmark for quality and provides the consumer certainty of the quality of pearl they have.

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.