Here we have a wonderful and large pair of Mexican screw Backs that will make a striking Summer accessory. They are hallmarked Silver Mexico under the screw back findings, although it has mostly rubbed away and 925 on the out side.
The old silver has mellowed to an incredible time enhanced patina. Their over all measurements are 2'' x 3/4''. I am not sure what the amethyst colored cabochons might be but they are gorgeous. They have a line through them that reminds me of a star sapphire. Amazing and in very nice vintage condition.