"Mesa and moon" names a family of landscape-and-sky devices documented in Southwest silver hallmarks. The most direct example is the mark of Navajo smith Tommy Moore — TOMMY MOORE STERLING with a mesa and moon — alongside crescent-moon and horned-moon marks recorded across Navajo, Hopi, Isleta, and Apache work.
Start with the mark that gives this entry its name: Hougart records Tommy Moore, a Navajo smith known for cluster work and nugget sets, marking TOMMY MOORE STERLING "with a mesa and moon" — one mark co-stamped with Rickey Reeds. The flat-topped hill and the crescent above it: a Southwest horizon compressed into a stamp. The mesa appears alone in Hopi silver, too — Hougart notes "the short hill (or 'mesa') stamp has been attributed to Kewanwy." (HOUGART ~lines 21336–21337, 18181)
The moon side of the family is bigger. The most important moon device in Southwest silver is institutional: the Navajo horned moon symbol, the registered trademark of the Navajo Guild, filed with the U.S. Patent and Trademark Office in 1943 and still in use through the Guild's successor, the Navajo Arts and Crafts Enterprise. Jim Harrison marks J H inside a horned moon symbol; Andy Lee Kirk of Isleta marked with crescent moons; Billy Ray Hawee (Hopi) used a crescent moon below a four-point star; an Apache smith is recorded with "a partial or crescent moon" mark; and Wright's Hopi registry records a Crescent Moon hallmark as well. (HOUGART ~lines 1483–1485, 15163, 15374, 15505, 18237, 31963–31965; WRIGHT ~lines 4641–4644)
The crescent shape itself is older than any hallmark. In Adair's record of the earliest Zuni silverwork, the first generation of smiths describes making earrings that "were flat and shaped like a crescent moon" — moon-shaped silver was being worn in the 1870s, before turquoise was ever set in silver there. Honesty requires saying what the corpus does not say: these sources document mesa and moon devices as hallmarks and design forms. They do not document a ceremonial meaning for the pairing, and we won't invent one. (ADAIR ~lines 24490–24497)
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