Thank you, we are fairly certain the cameo is shell, the background is a pale pink and it is a woman's face looking left with her hair up. I wish I could get a picture of the hallmark but it is very small as the ring band is thin. The camera won't capture it clearly.
Rating
10kt Ring - E in a diamond by: Yvonne
Mae
thanks for writing in! We found a Jewelry manufacturer in New York that has the mark: E in diamond.
And
Jewelry manufacturer (Toronto & Elsewhere in Canada) in your locality: E in diamond - E.T. EATON & CO. Retailers Chain ca 1890s-1999. Most probably the Canadian Jewelry manufacturer of your cameo ring setting. If I can see the mark could confirm. Mae is the cameo shell and what is the subject?