Georgia O’Keeffe did. Part of her self styling for photographs was a whimsical pin made for her by Alexander Calder in 1934. It spelled out her initials, “OK.” However, she usually wore it vertically so that looked more abstract. Unless you knew to look, you might miss the letters.
The original was made in brass, but she loved it so much she had it coped in silver on a trip to India. The silver version is a frequent accessory in photos as she aged, a compliment to her silver hair.
I know lots of people with signature jewelry pieces, from necklaces to bracelets, but I don’t have one. Maybe I should invest in a Calder pin on ebay selling for a mere $112,000, and only $500 shipping! Alas, it is just an “O” shape, not matching any of my initials.