there are a number of US jeweler retailers that have a mark like this. You might have to use the powers of deduction to work this one out.
I would approach the following company as they are still around and make enquiries about the vintage hallmark on your delightful cultured or imitation pearl bracelet; I doubt very much these Pearls are Natural Pearls.
Just curious, how are these pearls attached to the sterling silver stations?
Anyhow, Keystone Silver Co. use the K maker's mark letter, same style K and all, within a different shaped shield but that's not all that unusual. Sometimes you may find the shield changes. It could be a wonky punch mark.
KEYSTONE SILVER Co. (on Sterling & Silver wares, Philadelphia, PA, USA) - ca 1914 - Present
You might try looking in the Jewelry Resources under the link - US Jewelry 1922.