Looking for favorite author from Young Adult section of library, during early 70s. One plot involved a girl who was having trouble with her racial identity (she was half black) and while on a class trip to a museum, she is transported back to Egypt where she is a princess.
This sounds to me a bit like Wraiths of Time by Andre Norton. However the heroine, Tallahassee Mitford, is an archeologist and is transported back to ancient Egypt when she grasped an ancient artefact.
There must be lots of books using variations on this plot device.