Encyclopedia of Japanese Minerals (Go to Intro Page)
by Alfredo Petrov
Minerals Starting with "U"
UCHUCCHACUAITE (uchukuchakua-koh; uchyukuchyakua-koh)
Hokkaido: Lustrous, longitudinally-striated prismatic crystals to several mm long (but usually 0.5 to 2mm) embedded in massive pink rhodochrosite, or in drusy vugs, in the Tsudo vein at the Inakuraishi mine, associated with galena, sphalerite, pyrrhotite and colorless drusy quartz, are probably the worldÕs best for the species. Also as micro-acicular crystals with diaphorite and acicular owyheeite in vugs at the Tohya mine. Caveat emptor: some specimens sold as uchucchacuaite have been only strange galenas or other minerals. On the other hand, some Hokkaido specimens previously sold as "fizelyite" are in reality uchucchacuaite.
"UDUMINELITE"
("UZUMINELITE" would have been a better english transliteration.)
Fukushima: The type locality for this inadequately described hydrous calcium-aluminum (oxy)phosphate -Ca3Al8(PO4)6 O6 .2H2O or Ca3Al8(PO4)2 O12 .2H2O - is the Uzumine feldspar mine, where it forms aggregates of white acicular orthorhombic crystals to 2mm long in cracks in perthitic feldspar in a pegmatite intrusion into a peridotite xenolith in granodiorite. Exhibits cleavage on {110} at nearly 90 degrees. (RI 1.623-1.626-1.631; 2V 76 44')
URALBORITE (uraru-hoh-seki)
Okayama: Very rare, grey prisms at Fuka, associated with white sibirskite, occasionally with borcarite.
URANINITE (sen-uran-koh; pitchblende = rekisei-uran-koh)
Fukuoka: In pegmatites at Kotohge, Kawasaki-machi, as blocky crystals to 4mm embedded in reddish feldspar, with smoky quartz and monazite. Some of it is intimately mixed with carbonaceous matter as "thucholite". A uraninite from here gave analysis (as wt% oxides) U 87.19, REE 5.84, Th 5.68, Pb 0.13, Fe''' 0.13, insol 1.03 (Kimura, T. and Iimori, T. (1936) Monazite, uraninite, and autunite from Japan. Geol. Soc. Japan Journ., 43, 450-452). Also in Masaki and Shimomasaki (same area as Kotohge???).
Fukushima: With iimoriite-(Y) as disseminated grains in quartz-microcline rare-earth pegmatites at Suishouyama. An analysis from here gave (as wt% of oxides) U4+ 55.40, U6+ 22.23, (Y,Er) 14.60, Th 3.86, Pb 1.01, Nb 0.74, Al 0.44, (Ce,La) 0.41, Fe3+ 0.17, Si 0.11, C 0.28, water 0.50 (T. Iimori (1941) The microgranular uraninite from Iisaka and its absolute age. Am. Jour. Sci., 239, 819). Similar association at Fusamata. Also at Sanchohme, and in the Uzumine feldspar mine, and in the Ishikawa district.
Gifu: As black films, with minor yttrium and lead, in molybdenite-bearing aplite veins at the Hirase mine, where it can constitute up to 0.4% of the veins. Black friable "pitchblende" masses to 25cm in Toki.
Ishikawa: Nagatejima.
Miyagi: Uraninite at the Matsuiwa mine, commonly of colloform texture, occurs mainly in the tourmalinized zone, rarely the silicified zone, of early Cretaceous altered andesitic rocks once mined for arsenopyrite. Also at Ouhari.
Shimane: In a tungsten-molybdenum-bearing vein at the Komaki mine.
Tottori: Associated with coffinite, ningyoite, gypsum and pyrite in reducing environment of a Neogene basal conglomerate overlying granitic rock in the Ningyoh-tohge epigenetic uranium district.
URANOPHANE (uranofen-seki)
Fukushima: In the Ishikawa district, and at Suishohyama.
Tottori: In petrified wood and carbonaceous matter in the oxidized portions of epigenetic uranium deposits in Pliocene lacustrine basal conglomerate overlying granite in the Ningyoh-tohge district.
URANOPILITE (uranopiru-seki)
Tottori: In the Tohgoh mine, as thin films or disseminations in oxidized parts of a Pliocene basal conglomerate overlying granitic rocks.
USHKOVITE (ushukofu-seki)
Hyougo: Associated with vivianite, mitridatite, rockbridgeite, beraunite and jahnsite-(CeFeFe) in a vug in the center of a single 3cm vivianite nodule from a Quaternary clay bed exposed in a Seishin-Chuhou roadcut at Oshibedani in Kobe city. Locality now covered with concrete. (Shimokoshi, et al (1996) Structure analysis of ushkovite, (Mg,Fe'')Fe'''2(PO4)2(OH)2.8H2O. Abstr. Annual Meeting of Miner. Soc. Japan 209 (in japanese).)
UVAROVITE (kai-kuromu-zakuro-ishi; more generically kuromu-zakuro-ishi)
Aichi: As grains less than 1mm size, with chromite in serpentinite at the Yoshikawa nickel mine.
Ehime: Thin green druses to several cm wide, in fissures in chromite ore at the Akaishi mine.
Hokkaido: Thin druses of emerald-green uvarovite microcrystals occur in Biratori-cho, associated with crusts of likewise tiny xls of violet-pink chromian clinochlore as a network in chromite ore. Nukabira chromium mine ((same place??)). Also as bright green agregates to 8cm in whitish chrysotile masses ((from Cr mine or one of the Hokkaido asbestos mines in Furano-shi????????????)). Also from the Nittoh mine and from Usapu.
Okayama: Minute (0.01mm) xls disseminated in greenish black serpentine (serpentinized harzburgite) near the Ohsayama white jadeite deposit. Associated with very rare 0.1mm kosmochlore (qv) crystals. (Sangun metamorphic belt.)
Ouita: Reported from the Washidani chromite deposit. (Confirmed uvarovite, or the dubious species "japanite" ??- qv.)
Tottori: At the Hirose mine and the Wakamatsu mine.
UYTENBOGAARDITE (uittenbogaado-koh)
Shizuoka: Reported from the Kawazu mine, but needs confirmation.
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