Albino oyster: the white oyster that makes black pearls
Such as in many other animals, the albino oyster, the one that nature forgot to color, is very rare. Those oysters have a white shell and surprisingly an orange pulpit. They are rare because the dark color of the oyster enable it to hide from predators by camouflaging in dark spots. Therefore, albino oysters, are a way more visible and are more vulnerable to predation.
In pearl farming, those oysters can still be grafted because like the other « normal » ones they have a pearl pouch where the nucleus and the graft tissu can be introduced. They will give as similar pearls. However, they cannot be used to make the graft tissus cause they are only able to produce non-pigmented mother of pearl, white, while tahitian pearls are famous for their colors, so there is no point using them as donor oysters.