URANOSPINITE
Ca(UO2)(AsO4)2 · 10H2O,
calcium uranyl arsenate hydrate
Uranospinite, a secondary mineral best known from the oxidized zone of arsenic-bearing uranium deposits, was found on 1100 level in the Sterling mine in the late 1970s, where it formed dull-lustered, yellow crusts on marble. A specimen in the Richard Bostwick collection, currently in the collection of the Franklin Mineral Museum, is dated May 19, 1978, and probably represents one of the earliest examples recovered. The mineral had not previously been known from the Franklin-Ogdensburg area. A set of mine maps in our possession shows the uranospinite locality at the western end of 1220 crosscut, at approximate mine coordinates 1220N, 570W, near the southeastern corner of the cross member (but in marble, not ore), only 2-3 m east of the 1100-level realgar locality in the same crosscut.
Initially the yellow crusts were simply termed “Unknown no. 5,” a temporary label given to them by Dr. Pete J. Dunn of the Smithsonian Institution. Later, however, Dr. Dunn identified the mineral as uranospinite via X-ray diffraction of a second specimen submitted to him by miner John Kolic. An October 12, 1981, letter documenting the identification is on file at the Sterling Hill Mining Museum.
Uranospinite to date is known locally only from the Sterling mine, and specimens from the initial occurrence are few. Richard Bostwick estimated that only about six or seven pieces were recovered from the 1100-level locality. However, King et al. (2021, p. 991) show uranospinite in “minute flecks” associated with meta-ankoleite, pyrochroite, alleghanyite, probable serpierite, and barite on a fracture surface in willemite-franklinite-calcite “red ore” from Sterling Hill, implying more than one find of the mineral, and further state (p. 1128) that uranospinite is “often associated with znucalite,” another of the secondary uranium species known from the mine.
References
Bostwick, R.C. (1992), The check list of Franklin-Sterling Hill fluorescent minerals. The Picking Table, vol. 33, no. 2, p. 10-11. [Mentions color of fluorescence of Sterling Hill uranospinite]
Bostwick, R.C. (2017), Fluorescent Minerals of Franklin and Sterling Hill, N.J., Part 2. The Picking Table, vol. 58, no. 1, p. 11-24. [Brief mention of uranospinite on p. 20]
Dunn, P.J. (1995), Franklin and Sterling Hill, New Jersey: the world’s most magnificent mineral deposits. Privately published, 755 p. [Short discussion of uranospinite on p. 684]
King, V.T., King, N.E., Betancourt, P.P., Bostwick, R.C., Chin, Peter, Hecht, T.J., Kuitems, S.M., Moritz, Harold, Nemetz, J.D., Nikischer, A.J., Sanford, Stephen, Van Fleet, J.A., and Verbeek, E.R. (2021), The Mineralogy of Franklin and Ogdensburg, New Jersey—A Photographic Celebration. Privately published, 1400 pp. [Several photographs of Sterling mine uranospinite on p. 205, 541, and 1128]
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