Blue Akoya Pearls get their distinctive blue color from a number of natural factors.

Nacre Composition-The are formed inside Pinctada fucata martensii oysters, which produce a nacre that sometimes has a high concentration of conchiolin which is an organic protein. This can create bluish or silver overtones.

Trace Elements and Minerals- The presence of certain trace minerals in the water where the oysters are cultivated may influence the color of the nacre towards the bluer tones.

Environmental Stress- Some Blue Akoyas get their color from stressful conditions like temperature fluctuation or changes in the water quality. 

Iridescence and Light Reflection- The way that light reacts with the microscopic layers of nacre can enhance the perception of blue hues, giving the pearls the silvery blue sheen.

Blue Akoyas are highly valued and lauded for their unique beauty because of these overtones of silvery blue, green or pink.