If one assumes the hallmark is oriented the same as the “sterling”, it is either an “M” or a double mountain peak over more mountain peaks? I have not been able to find a reference for this one online or in Hogart Native Am & Sw Silver or Wright Hallmarks of the SW. Any further info would be greatly appreciated.
This bracelet is classic 1980s’s Navajo work. The jewelry boom happening at this time had everyone making jewelry. These simple one letter hallmarks are some of the most difficult to find the name of the silversmith. Good luck.