Gold filled cameo of ladies head profile by: Anonymous
The marks mean that 1/5th of the entire weight of the Gold is 12 k gold. It was most probably not handed down to your grandmother but was gifted or bought "new" at the time. Your cameo is very pretty.
Rating
Early to mid 20th Century by: Anonymous
Hello Virginia
the numbers on the metal surround of your cameo brooch/pendant < 1-20-12k > means that 1/5th of the weight of the surround is comprised of 12 k gold. The metal is made from gold filled which is like a sandwich of gold sheets between a base metal. It is the outer sheet of 12k that touches the skin.
It would be early mid 20th century, the letters are the maker marks. When you have identified the maker you will be able to date the piece with more precision.
The color of the material has the appearance of organic material like conch shell but not sure.
