Am not a vendor, (Is there an echo in here?), but cream is a natural color. Many whites are bleached although some are naturally colored. There are many shades of peach to pink, mauve to lavender and both blue and green overtones are natural. I have also seen a number of yellow and gold pearls that were not dyed. Christmas red is never natural although there are some beautiful red overtones on Tahitians in another thread somewhere here. I have also seen a few metallic pearls that are copper or brown in color. I have a number of silvery CFW that have a pale lavender or grey base color.
What I don't see are primary colors. Red-red. Stand alone blue. Yellow with no overtone or undertones. Although I adore gold pearls and some of them are gold with gold overtones in both CFW and SSP's.
Of course you know that white can have almost any over tone.
Hope that helps.
barbie
It'll be a mystery to me 'till I pass beyond the veil why vendors color pearls peach, white, lavender. As if those are the only colors.
Actually, that's a lie. I suspect they do it to get more even colors with less than perfect pearls.