No you clip it on your belt to hang a purse or chatelaine. Google silver chatelaine hook for more examples. At the moment i am travelling, no access to my library. Will confirm maker's mark after 23rd of April.
Yes, the hook is puzzling in regard of chatelaine. I recall a forum member from Denmark (I think) asked about the function of similar item and then explained it was for embroidery girls worked on and kept them on hook attached to the belt whenever they needed to go around. Regards