Crystal Data: Orthorhombic. Point Group: mm2. Commonly in crystals, tabular || {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 in

transmitted light. Streak: Yellow. Luster: Adamantine.

Optical Class: Biaxial (--). Pleochroism: X = almost colorless; Y = Z = lemon-yellow to

golden yellow. Orientation: X = c; Y = b; Z = a. Dispersion: r > v, strong.   alpha = 1.690(3)

beta = 1.714(3)  gamma = 1.735(3) 2V(meas.) = 75°–85°

Cell Data: Space Group: P2₁ca.   a = 14.337(3) b = 16.813(5) c = 14.731(4) Z = 8

X-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:                                                         (1)                  (2)

                                                    UO₂               87.73             87.59

                                                   H₂O               12.32              12.41

                                                   Total                                   100.00

(1) Shaba Province, Congo; UO₃ average of four partial determinations, H₂O average of two

partial determinations.  (2)  (UO₂)₄O(OH)_6· 6H₂O.

Occurrence: A rare alteration product of uraninite in hydrothermal uranium deposits; may

form directly from ianthinite.

Association: Uraninite, becquerelite, billietite, vandendriesscheite, fourmarierite, ianthinite,

curite, soddyite, rutherfordine, uranophane (Shinkolobwe, Congo); paraschoepite, arsenuranylite,

metazeunerite, uranospinite, novacekite (Charkasar, Uzbekistan).

Distribution: From Shinkolowbe, Shaba Province, Congo (Zaire). In the USA, at Beryl

Mountain, Acworth, Sullivan Co., New Hampshire; in Utah, at the Consolidated mine, Green Vein

Mesa, Emery Co., the Happy Jack mine, White Canyon, and the Frey No. 4 mine, Red Canyon,

San Juan Co., and the Oyler Tunnel claim, near Fruita, Wayne Co.; from the Monument No. 2

mine, 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., New

Mexico; in the Lucky Mc mine, Gas Hills district, Fremont Co., Wyoming. From Wölsendorf,

Bavaria, Germany. In the Margnac mine, Compreignac, Haute-Vienne, and at Mas-Alary, Hérault,

France. In Japan, at Akura, Okayama Prefecture, and in the Tarumi mine, Kagoshima Prefecture.

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 and

thorium. U.S. Geol. Sur. Bull. 1064, 72–78.   (3) Toussaint, J. and H. Brasseur (1959) Sur la

structure 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 uranyl

oxide 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)₈O₂(OH)₁₂](H₂O)_12..

Can. Mineral., 34, 1071–1088.