We were lucky to find old cabochon pins as new old stock - never used - in a Brooklyn, New York warehouse. This one is a pink smiling face, but, as you can see in the second photo, there is no pin, just the mechanism to hold a pin. There is very little wear.
It appears that the cab is made of metal and that the image has been transferred onto the cabochon either by printing or some other method.
If you care to do so, you might re-work these into assemblage pieces by removing the cabochon and applying a new image, or, indeed by replacing it with something else. Please be careful if you choose to remove the cabochon - especially if you are bending the prongs.
This cute little pin was made by a novelty company - not a jewelry company - so please be careful when working with them.
It measures about 7/8 inch in diameter On the back, there is the mechanically attached pin holder. So, for a novelty, this are quite well made. We're not sure what happened to the pin, though.