R. Nakanishi's Photo Gallery

QD0-DHNArfvedsonite [Na][Na₂][Fe²⁺₄Fe³⁺]Si₈O₂₂(OH)₂ , Albite (Var: Anorthoclase) (Na,K)AlSi₃O₈

Usubae, Matsuo, Tosashimizu City, Kochi Prefecture, Japan

Dimensions: 68 mm x 58 mm x 23 mm

Unusual alkaline rhyolite collected from an outcrop near Cape Uno (Uno-misaki). The alkaline rhyolite consists mainly of fine bluish arfvedsonite and white anorthoclase, and occurs as dykes cutting granite. Moreover it is rich in REE and the presence of the following minerals has been reported: bastnäsite-(Ce), columbite-(Fe), gold (Ag-Fe-bearing), ilmenite, ilmenorutile, monazite-(Ce), thorite and zircon.

70L-QA1Quartz SiO₂ , K Feldspar (Var: Adularia) KAlSi₃O₈ , Clay

Sanjin deposit, Hishikari Au mine, Kagoshima Prefecture, Japan

Dimensions: 90 mm x 75 mm x 35 mm

High-grade gold ore from Hishikari mine, which is one of the few active metal mines in Japan. No gold minerals are visible in the photos (if you are not a "fool"), but microscopic electrum grains are present in the whole specimen (adularia-quartz vein in association with clay minerals) and in particular concentrate in clay minerals zone. Mined from Keisen No. 3 vein.

1F2-G1WCinnabar HgS , Dolomite CaMg(CO₃)₂

Tongren, Guizhou, China

Field of View: 20 mm

Transparent deep carmine crystals of cinnabar on matrix covered with colorless dolomite crystals.

F59-AWJGreenockite CdS , Sphalerite ZnS , Hedenbergite CaFe²⁺Si₂O₆

Kamioka Mine, Hida City, Gifu Prefecture, Japan

Field of View: 40 mm

Eye-catching vivid yellow greenockite on weathered sphalerite-hedenbergite matrix.

6UP-8D2Calcite (Var: Nickel-bearing Calcite) (Ca,Ni)CO₃

Podolsk Urban District, Moscow Oblast, Russia

Dimensions: 65 mm x 22 mm x 14 mm

Thin crust (up to 7mm) of greenish-yellow nickel-bearing calcite. Accompanying label says this calcite contains 0.2% nickel. A rarely available material.

F09-11ECalcite (Var: Cobalt-bearing Calcite) (Ca,Co)CO₃

Bou Azzer mining district, Drâa-Tafilalet Region, Morocco

Dimensions: 79 mm x 67 mm x 48 mm

Beautiful prismatic pink crystals of cobalt-bearing calcite in a vug in matrix. The whole vug is lined with smaller crystals. Each crystal has a nailhead termination. The color reminds me of spring in Japan in spite of its African origin.

XP8-1YWPyrite FeS₂

Ani Mine, Ani-machi, Kitaakita City, Akita Prefecture, Japan

Dimensions: 45 mm x 39 mm x 30 mm

Aesthetic cluster of dodecahedral pyrite crystals. Accompanied by Dr. Hidemichi Hori's label (founder of Hori Mineralogy).

H04-QE1Sphalerite ZnS , Galena PbS , Chalcopyrite CuFeS₂ , Tetrahedrite Subgroup Cu₆(Cu₄C²⁺₂)Sb₄S₁₂S , Tennantite Subgroup Cu₆(Cu₄C²⁺₂)As₄S₁₂S , Baryte BaSO₄ , Pyrite FeS₂

Takara mine, Tsuru City, Yamanashi Prefecture, Japan

Dimensions: 53 mm x 30 mm x 20 mm

Small chunk of Kuroko (black ore) from a deposit located in the southern Fossa Magna.

64M-X3VSphalerite ZnS , Galena PbS , Chalcopyrite CuFeS₂ , Tetrahedrite Subgroup Cu₆(Cu₄C²⁺₂)Sb₄S₁₂S , Tennantite Subgroup Cu₆(Cu₄C²⁺₂)As₄S₁₂S , Pyrite FeS₂ , Gypsum CaSO₄·2H₂O , Baryte BaSO₄

Shakanai Mine, Odate, Akita Prefecture, Japan

Dimensions: 135 mm x 100 mm x 55 mm

Massive specimen of Kuroko (black ore; "kuro" and "ko" mean black and ore, respectively). The vuggy chalcopyrite-rich zone is partially lined with small crystals of sphalerite and gypsum.
Most of the Kuroko-type deposits in Japan were formed by submarine volcanic activities associated with the formation of Japan Sea. Kuroko consists of many kinds of ore/gangue minerals, and its composition is so complex it could not be smelted until the early 20th century.

WQJ-GGRMohawkite, Quartz SiO₂ , Calcite CaCO₃

Mohawk Mine, Mohawk, Allouez Township, Keweenaw County, Michigan, USA

Dimensions: 145 mm x 105 mm x 35 mm

Cut and polished mass of mohawkite. Spherical aggregates of quartz and irregularly shaped calcite make it much more attractive.