This postcard of the Southwest Turquoise Co., 113 N. Broadway, has been listed on EBay. The shop would have been roughly across the street from the old Times Building at 1st and Broadway. Bidding on the postcard starts at $8.
Mrs. Gertrude S. Reynolds McMullen via the Herald.
The company’s cutting and polishing instrument was invented by a woman – Mrs. Gertrude S. Reynolds McMullen, a former science teacher who became interested in precious stones.
Clearly, she was ahead of her time in more ways that one.
She died in 1950 at the age of 78.
ladailymirror.com 
The last article refers to a “violet ray”, which sounds like sci fi but is undoubtedly an ultraviolet light. It demonstrates the florescence of minerals such as feldspar because they are RADIOACTIVE. If her workers handled such minerals, then anyone nearby would be exposed to dangerous levels of radioactive dust. Hope that powerful brain knew this.
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Most scientists at the time Ms. McMullen began her career were not that aware of radiation’s harmful effects, so perhaps she wasn’t, either. But not all fluorescent minerals are radioactive, we don’t know what minerals she was showing at her Soroptimist talk, and we don’t know that those were the same minerals being cut in her business, so there’s no reason to assume from these articles that she was harming her workers.
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Agreed, if her workers only made jewelry, and she probably wouldn’t deliberately harm her employees. But some U.S. factories used radioactive florescent minerals to paint watch and clock hands and faces, in utter ignorance of the long term health effects. Those old factories are now Superfund sites. Many of those workers, mostly women, died, so an epidemiological study of her workers would be determinative.
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