In my country, you are not allowed to mark anything as sterling silver without a hallmark as well. I do not know what the regulations on this are in other countries. Your hallmark has to be registered with the patent board, and you need to renew it every ten years. I registered mine in 2014 already, but have not come around to have a stamp made until early last year. It took some doing, with a bit communication on email, but my stamp was ready.
The reason is of course that when you claim something is consisting of a certain amount of silver, you need a guarantee that what you say is indeed correct. The hallmark makes you accountable for what you claim. I can now stamp larger pieces with the sterling stamp, following my hallmark stamp.
It is tiny, only 2 mm in diameter. I am only able to see it using magnifying glass, but that is normal – at least I hope it is. The stamp is my logo, which you also can also see in my shop on Etsy. The tiny handmade earring hooks cannot be stamped, I have no idea where to place it there. But larger pendants etc. might. Or, as shown here – on the back of two discs ready to be put in the tumbler. The yellow in the photo is a greeting from the afternoon sun.. This is how I usually place earrings in the tumbler. I use a copper wire wrapped around earrings that belong together, that way I do not have to sort them afterwards. Since everything is handmade, one pair can be different from another pair.