Recently we discovered these are a little large for a 25x18mm cameo. You will have to center it carefully. Otherwise you might use this setting for pictures or some other purpose. I am going to put this on sale. Limited quantity. This is a brass setting with a silver tone bright finish. This is not a true sterling silver plate. A bit greyer in color most often referred to as "white" by the industry. I see some suppliers calling it platinum in terms of "color" This settings comes with an easy lock pin back already soldered on it.