Many Chinese pearls used to be dyed in the 1980s to bright red, blue, lavender, yellow or even black. In response to contemporary preferences, they now offer a selection of subtle natural colors.

However, both natural and cultured pearls come in various colors of the rainbow — from white to black — including blue, green ...

He says that part of the reason the Marie Antoinette pearl is worth so much is because it's a natural pearl, which brings us to one quality that determines a pearl's value. Natural versus cultured.

Natural pearls are harder to find ... sought after for its seemingly infinite display of colors, compared to common opal, which is usually one color. High-quality black opal can cost over $ ...