I love Cameos, New and Vintage

I really love Cameos, new and old. The ring shown, my mother made for me for my birthday. It is a heavy silver, with a lilac and white cameo. I love it, and wear it often. The other two shown, I have had in my collection for many years. I think they are Intaglios but I am not sure. If anyone has any idea how to identify them, I would love to know. They do not appear to have any markings. The Brooch is of a Roman Soldier under glass, it is very colorful and 3D. The square cabachons are also Roman Soliders, and are 3D. I would love to know some more information on these, they are fascinating.