AMANDA Alexander’s family has been in the jewelry business in Santa Fe, N.M., for 44 years, employing artisans to create Native American pieces for women. Growing up, Ms. Alexander’s brother and male friends didn’t get why anyone would wear jewelry: “They would be like, ‘We don’t understand it, what’s it all about?’” Still, three years ago, when Ms. Alexander joined Peyote Bird, the company her father founded, she decided to launch a men’s jewelry collection, seeing an opportunity. Today, it’s Peyote Bird’s fastest-growing category.

Still,...