Black pearls are not necessarily black. There is a rainbow of color varying from black, to dark or light gray, dark or light green, pinkish, blue and bronze-brown. Some pearls are even bi-color. A few years ago the trend was toward black pearls with green overtones, but nowadays lighter color are very popular, due to the growing interest and appreciation of the wonderful color spectrum of the Tahitian variety. You should always select pearls in colors that you like and will look flattering on you.
Black pearls reflect light in a different way than white pearls do.
There is a total different perception of colors and shine, even if of same shape. Round and semi-round are the most expensive and rare pearls, followed by drop and button shapes. These shapes make really stunning and important jewelry. Circled and baroque pearls are a real bargain and offered at a much lower price, but they still make wonderful and unique jewelry with personality and flair as well. The roundness depends on how long a pearl is left in the oyster underwater because of water friction that can work it into different shapes.