realgar

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Occurrence of sulphur, orpiment, and realgar in the Yellowstone National Park
Walter Harvey Weed and L. V. Pirsson

American Journal of Science November 1891, s3-42 (251) 401-405; DOI: https://doi.org/10.2475/ajs.s3-42.251.401
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Occurrence of realgar and orpiment in Utah
William Phipps Blake

American Journal of Science March 1881, s3-21 (123) 219; DOI: https://doi.org/10.2475/ajs.s3-21.123.219