Schoepite(UO2 )4 O(OH)6 • 6H2 Oc 2001-2005 Mineral Data Publishing, version 1

Crystal Data: Orthorhombic. Point Group: mm2. Commonly in crystals, tabular k {001},equant, may be short prismatic along {001}, to 1.5 mm; highly developed, with over 20 forms
noted; rarely in microcrystalline aggregates.
Physical Properties:
Cleavage: {001}, perfect. Tenacity: Brittle. Hardness = ∼2.5
D(meas.) = 4.8–4.96 D(calc.) = 4.87 Radioactive; fluoresces green under UV.
Optical Properties: Transparent. Color: Sulfur-yellow to citron-yellow; brownish yellow
to amber-yellow, as a surficial alteration towards metaschoepite and paraschoepite; yellow intransmitted light. Streak: Yellow. Luster: Adamantine.
Optical Class: Biaxial (–). Pleochroism: X = almost colorless; Y = Z = lemon-yellow togolden yellow. Orientation: X = c; Y = b; Z = a. Dispersion: r > v, strong. α = 1.690(3)β = 1.714(3) γ = 1.735(3) 2V(meas.) = 75◦ –85◦
Cell Data:

Space Group: P 21 ca. a = 14.337(3)b = 16.813(5)c = 14.731(4)Z=8X-ray Powder Pattern: Shaba Province, Congo.
7.35 (100), 3.66 (50), 3.24 (9), 2.446 (9), 2.571 (4), 3.21 (3), 3.162 (3)Chemistry:UO3
H2 O(1)
87.73
12.32

(2)
87.59
12.41

Total
100.00(1) Shaba Province, Congo; UO3 average of four partial determinations, H2 O average of two
partial determinations. (2) (UO2 )4 O(OH)6 • 6H2 O.
Occurrence: A rare alteration product of uraninite in hydrothermal uranium deposits; mayform directly from ianthinite.
Association: Uraninite, becquerelite, billietite, vandendriesscheite, fourmarierite, ianthinite,curite, soddyite, rutherfordine, uranophane (Shinkolobwe, Congo); paraschoepite, arsenuranylite,metazeunerite, uranospinite, nováčekite (Cherkasar deposit, Uzbekistan).
Distribution: From Shinkolobwe, Katanga Province, Congo (Shaba Province, Zaire). In theUSA, at Beryl Mountain, Acworth, Sullivan Co., and in the Ruggles mine, Grafton, and thePalermo mine, near North Groton, Grafton Co., New Hampshire; in Utah, at the Consolidatedmine, Green Vein Mesa, Emery Co., the Happy Jack mine, White Canyon, and the Frey No. 4mine, Red Canyon, San Juan Co., and the Oyler Tunnel claim, near Fruita, Wayne Co.; at theLookout No. 22 claim, Marshall Pass district, Saguache Co., Colorado; from the Monument No. 2mine, Apache Co., the Abe Lincoln mine, northeast of Wickenburg, Yavapai Co., and the Black
Point-Murphy mine, near Cameron, Coconino Co., Arizona; from Paguate, Valencia Co., NewMexico; in the Lucky Mc mine, Gas Hills district, Fremont Co., Wyoming. From Wölsendorf,Bavaria, Germany. In the Margnac mine, Compreignac, Haute-Vienne, and at the Mas-d’Alaryand Rabéjac uranium deposits, south of Lodève, Hérault, France. In Japan, at Akura, Okayama
Prefecture, and in the Tarumi mine, Kagoshima Prefecture. From the Cherkasar uranium deposit,
Chaktal Mountains, Uzbekistan. Several additional localities are known.
Name: Honors Alfred Schoep (1881–1966), Professor of Mineralogy, University of Ghent, Ghent,Belgium, for his contributions to uranium mineralogy.
Type Material:

Royal Ontario Museum, Toronto, Canada, M13072.

References: (1) Palache, C., H. Berman, and C. Frondel (1944) Dana’s system of mineralogy,(7th edition), v. I, 627–628. (2) Frondel, C. (1958) Systematic mineralogy of uranium andthorium. U.S. Geol. Sur. Bull. 1064, 72–78. (3) Toussaint, J. and H. Brasseur (1959) Sur lastructure de quelques composés uranifères hydratés. Bull. Cl. Sci. Acad. Roy. Belg., 45, 501–506(in French). (4) Christ, C.L. and J.R. Clark (1960) Crystal chemical studies of some uranyloxide hydrates [schoepite-I]. Amer. Mineral., 45, 1026–1061. (5) Finch, R.J., M.A. Cooper, F.C.
Hawthorne, and R.C. Ewing (1996) The crystal structure of schoepite, [(UO2 )8 O2 (OH)12 ](H2 O)12 .
Can. Mineral., 34, 1071–1088.
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