Well with that family provenance, and from its appearance in the pics. I'd say your family has a fabulous natural pearl and diamond brooch.
Can you share the size of the large pearl drop with us?
The gray tinge of the drop leaves the pearl's origin wide open. At a guess I'd say the brooch may be French or Belgian, circa 1900, and the gray drop could be a natural South Pacific pearl from one of the French Polynesian territories of the time.