They are gold colored with no markings. They are very old, 70+ years as they were my mothers. My mother was Irish born in Mexico for my Grandfather ran a smelting plant there. A lot of metals from Mexico made into jewelry came out unmarked in the 30's and 40's. I hope this answers both of your questions. They are beautiful.
Oh and before there is anymore confusion, they were screw back for my mother until she passed. Then my father converted them to pierced for me which may and I'm serious about may, have removed the jewelers mark.