Judging by their color, they appear to be beautiful Black Pearls. If purchased from Jeweller in London, one would think your pearls would be of good quality. The color of pearls is not connected to their luster. In general, the color of pearls is usually the same as that of the shell in which they are formed. Black pearls are found in the black pearls of, Mexico and other localities and pink pearls are found in the pink hued "Strombus" of the Bahamas. However there are exceptions.
Are your pearls knotted - between each one of the pearls? Examine the drill hole - is it small? Small drill holes are a sign of quality. To avoid loss of weight in high quality pearls, the drill hole will be made as small as possible.
Examine the clasp. Is it marked? Do you know the metal type? A high quality clasp indicates high quality Pearls.
