Hi Jan
A few tips for photographing pearls you could try are....
Use a dark background, preferablly black and photograph the pearls from an angle rather than from over head.
Photographing many things from the side at a slight angle can help reduce reflection.
Another way to try is to get an empty plastic, frosted milk carton, ideally the large size. Cut the bottom of the bottle off and cut the top so your camera lense fits inside and place the bottle over your item, then photograph the item through the top of the bottle. This method acts as a difuse filter frosting the strong light. Is best done in natural light. Try these methods it may work.
