Without a hands on inspection...they both appear to be shell. Did you have it cleaned at a jeweler? Did they know anything?
The reason I ask this is that the jewelry store near us has me identify cameos for them - they just don't get that many to appraise and you do really need to have a "hands on" unless you have family history.
Cameos can be made of shells, stone, bone, lava, etc.... The clasps are a hint as well to age.
The one on the left - style of metal work appears to be from the early to 30's and can't tell from the second one from the angle of the shot. However, the Roman nose on her is typical of Victorian style cameos. Also, curious about the chain?!?
Can you get a better close up of the fronts and backs individually?
