The Victorian's had a very macabre sense of remembering their loved ones which sometimes involved pieces of their hair and commonly enamelled. The various colours of enamel used represented whether or not the person was married. Black was used to show mourning of a married person, whereas white would be used for unmarried people, which was less common.
Rings that mark the memory of someone are not a new concept and in fact date back to Roman times (1st Century AD). Where rings could show a carving of Cupid leaning on an extinguished reversed flame (torch) symbolising death. In the middle ages the concept is seen too with images of skulls and skeletons.