PREFECTURAL STONES OF JAPAN

The Geological Society of Japan has selected a rock, a mineral and a fossil that represent each of 47 Prefectures of Japan, and presented the selection list to the public on 10 May 2016, the Geology Day in Japan. Either geologically, industrially or historically important stones that occur in respective Prefectures are selected. The English version of the list is given below where Prefectures are arranged from North to South. This is an outreach action of the Society in commemoration of its 125th Anniversary that is expected in 2018. Other anniversary-related actions of the Society include cooperation for publication of "The Geology of Japan" (published by the Geological Society of London in April, 2016), support for the 10th International Earth Science Olympiad (20–27 August 2016 at Mie, Japan), and publication of a number of timely, comprehensive reviews on various fields of geological sciences in the Society's journals; "The Journal of the Geological Society of Japan" and "Island Arc". We hope international audience can get quick insights into geological richness of the archipelago and useful materials to make geological communication with its dwellers by the list of Prefectural Stones of Japan. The Geological Society of Japan Presidents: Akira Ishiwatari (2012–2013) Yasufumi Iryu (2014–2015) 県の石 Yoshio Watanabe (2016–present)

Prefecture (Capital) Rock (Place) Mineral (Place) Fossil (Place)

Peridotite [very fresh alpine-type mantle "Placer Platinum" [In fact, iridosmine; ammonites [Well preserved, lherzolite with garnet pseudomorphs washed out from highly refractory mantle ammonites, up to >1 m in diameter, are 1. Hokkaido (Sapporo) (spinel-pyroxene symplectites); peridotite and serpentinite of Horokanai abundantly found from the Cretaceous registered as UNESCO geopark in 2015] Ophiolite] (Central Hokkaido; Sorachi, forearc deposits] (Central Hokkaido, (Horoman, Samani) etc.) Sorachi, etc.)

"Nishiki Ishi" [iron-rich, red chalcedony; Rhodocrosite [mangan spar; pink "Aomori Mukashi Kujira 2. Aomori (Aomori) Miocene hydrothermal product] (Occurs manganese carbonate; Miocene Uo" [Miobarbourisia aomori; Miocene widely) hydrothermal product] (Oda Mine) whalefish] (Arakawa River, Aomori)

"Naumann Yama Momo" [Comptonia Siliceous mudstone [Miocene Onnagawa Kuroko deposits [Miocene massive naumanni; fossil plant (sweetfern) of 3. Akita (Akita) Formation, source rock of Akita oil field] sulfide ore formed around sea-floor Miocene Daijima Flora] (Occurs widely in (Oga Peninsula) vents] (Hokuroku area) this prefecture)

Serpentinite [Mantle section of Iron-rich skarn ore [provided enough iron corals [The first discovery of 4. Iwate (Morioka) Ophiolite] (Mt. Hayachine, for Japan's modernization] (Kamaishi Silurian deposits in Japan was based on Kitakami Mts.) Mine) these fossils] (Hikoroichi, Ofunato)

Dacitic tuff [Basement rock of the "Soroban-dama Ishi" [Abacus-piece "Yamagata Kaigyu" [Dusisiren dewana; 5. Yamagata (Yamagata) Buddhist temple famous for Basho's chalcedony] (Oguni) Miocene sea cow] (Oe Town) haiku] (Yamadera, Yamagata)

Placer Gold [The oldest gold mine of "Utatsu Gyoryu" [Utatsusaurus hataii; the slate [inkstone] (Toyoma Fm.; Japan in the 8th Century; contributed to earliest-known ichthyopterygian which 6. Miyagi (Sendai) Ogatsu, Ishinomaki and Tome) decorate Great Buddha in Nara] lived in the early ] (Utatsu, (Nonodake, Wakuya) Minami-Sanriku)

Cretaceous Gneiss [Originated in Pegmatite minerals [quartz, feldspar, "Futaba Suzuki Ryu" [Futabasaurus 7. Fukushima (Fukushima) accretionary complex] mica, tourmaline, etc.] (Ishikawa) suzukii; Cretaceous plesiosaurs] (Iwaki) (Abukuma Mts.)

Elbaite [Lithium tourmaline in lithium Stegolophodon [Miocene elephant] 8. Ibaraki (Mito) Cretaceous Granite (Mt. Tsukuba) pegmatite] (Mt. Myoken, Hitachi-Ota) (Hitachi-Omiya)

"Konoha Ishi" [Leaf Stone; Pleistocene "Oya Ishi" [Miocene green tuff, widely 9. Tochigi (Utsunomiya) Chalcopyrite (Ashio Copper Mine) plant fossils in lake deposits] (Shiobara, used for fence blocks] (Oya, Utsunomiya) Nasu)

"Oni Oshidashi Yogan" [Andesite block Realgar [Arsenic sulfide; Late Miocene "Yabe Otsuno Jika" [Sinomegaceros 10.Gunma (Maebashi) lava of Asama Volcano erupted in 1783] hydrothermal ore, an item of Shimonita yabei; Plio-Pleistocene giant ] (Tsumagoi Village) Geopark] (Nishinomaki Mine, Shimonita) (Kamikuroiwa, Tomioka)

Schist [Cretaceous high pressure Stilpnomelane [Calcium-bearing mica- Paleoparadoxia [Miocene sea 11.Saitama (Saitama) Sanbagawa metamorphic rocks] like mineral occurring in Sanbagawa (family Desmostylidae)] (Hannya, Ogano; (Nagatoro) schist] (Nagatoro) Onohara, Chichibu)

"Boshu Ishi" [Tuffaceous sandstone and Chibaite [silica clathrate including Molluscan shells in the Upper 12. Chiba (Chiba) granule conglomerate used as building methane and ethane] (Boso Peninsula; Pleistocene Kioroshi Shell Bed (Kioroshi, stones] (Nokogiriyama, Futtsu) Miocene accretionary complex) Inzai)

1 Prefecture (Capital) Rock (Place) Mineral (Place) Fossil (Place)

"Munin Gan" [Boninite; Eocene highly Clinoenstatite [highly magnesian "Tokyo Hotate" [Mizuhopecten 13. Tokyo Metropolis magnesian andesite] (Chichijima Island, pyroxene in boninite] (Chichijima Island, tokyoensis; Plio-Pleistocene scallop] (Oji, (Tokyo) Ogasawara (Bonin Islands)) Ogasawara (Bonin Islands)) Kita-ku and elsewhere)

Miocene scleractinian corals (Tanzawa Tonalite [Pliocene potash-poor granite 14. Kanagawa Yugawaralite [calcic zeolite that was first Mts.; formed on a volcanic island of the (plagiogranite, quartz diorite)] (Tanzawa (Yokohama) discovered from Yugawara] (Yugawara) Izu-Bonin-Mariana arc that collided with Mts.) Japan)

Jadeitite [product of Cambro–Ordovician Native Gold [Miocene vein-type gold- -Permian marine fossils 15. Niigata (Niigata) subduction metamorphism] (Omi and silver ores] (Sado Gold Mine, Sado [from the "Omi Limestone"] (Omi, Kotaki, Itoigawa) Island) Itoigawa)

Obsidian [Pleistocene welded rhyolitic Garnet [spessartine garnet that occurs in "Naumann Zo" [Paleoloxodon naumanni; 16. Nagano (Nagano) tuff; used as arrow heads by lithic age cavities of the Wadatoge rhyolite] Pleistocene elephant] (Lake Nojiriko) people] (Wadatoge Pass) (Wadatoge Pass)

Rock Crystal [Quartz] twinned in Basalt Lava of Fuji Volcano [erupted in Late Miocene molluscan shells in the 17. Yamanashi (Kofu) accordance with Japan law [also known 864-866 A.D.] (Aokigahara Forest) Fujigawa Formation (Obarajima, Minobu) as Japanese twin] (Otome Mine)

Onix Marble [Travertine, Miocene sea- Staurolite [in Permian medium-pressure Miocene molluscan shells in the Yatsuo 18. Toyama (Toyama) floor hydrothermal carbonate rock] type Unazuki metamorphic rocks] Group (Yatsuo, Toyama) (Shimotate, Unazuki) (Uchiyama, Unazuki)

Diatomite [Diatom mudstone; Miocene Aragonite [Occurs in cavities of Miocene Early Pleistocene molluscan shells in the 19. Ishikawa (Kanazawa) shallow sea and lake deposits] (Noto basalt lava] (Koiji beach, Noto Town) Omma Formation (Okuwa, Kanazawa) Peninsula)

"Shakudani Ishi" [Miocene lapilli tuff Native arsenic [Spherical aggregate of Fukuiraptor kitadaniensis [Dinosaur 20. Fukui (Fukui) excavated for long time as industrial rock euhedral crystals like a comfit sugar] excavated from the Cretaceous Tetori material] (Akatani Mine, Fukui) Group] (Kitadani, Katsuyama)

"Akaiwa" [Red rocks forming the Hoei Early Pleistocene molluscan shells in the crater, the site of 1707 eruption of Fuji Native tellurium [occurs with tellurite and 21. Shizuoka (Shizuoka) Kakegawa Group (Dainichi Formation) Volcano. The rocks comprise volcanic kawazulite] (Kawazu Mine, Shimoda) (Kakegawa and Fukuroi) lapilli and ash] (Hoei Kako, Gotemba)

Middle Miocene deep-sea fossils in the Pitchstone [Miocene rhyolitic rocks Kaoline [source clay for the Seto Morosaki Group [Crinoids, devilfish, sea 22. Aichi (Nagoya) forming Shitara Cauldron] (Mt. Horaiji, potteries] (Seto) urchins, fish, bivalves, gastropods, etc.] Shinshiro) (Chita Peninsula)

Chert [Bedded radiolarian chert of Hedenbergite [Fe-Ca Pyroxene in skarn Permian marine fossils in the "Akasaka Triassic-Jurassic age in the Jurassic deposites] (Kamioka Copper-Zinc Mine, Limestone" [Fusulinids, bivalves, 23. Gifu (Gifu) accretionary complex of Mino Belt] Hida (Mine is closed, but is used as gastropods, crinoids, etc.] (Akasaka (Unuma, Kagamihara; Sakashuku, Kamo) Kamiokande to detect nutrino)) Kinshozan, Ogaki)

Kumano rhyolitic volcanic rocks [Miocene Cinnabar [Quicksilver (mercury) deposits "Mie Zo" [Stegodon miensis; Pliocene 24. Mie (Tsu) caldera volcano in the forearc area] formed in the Ryoke and Sanbagawa elephant] (Tsu, Kameyama, Iga, Suzuka, (Southeastern Kii Peninsula) belts in Miocene] (Nyu Mine) Kuwana, etc.)

Footprints preserved in the Kobiwako Koto Rhyolite [Late Cretaceous large- Topaz [Pegmatite mineral in Cretaceous Group [Plio-Pleistocene deer, elephant, 25. Shiga (Otsu) scale caldera volcanism] (Higashi-Omi granite] (Tagamiyama, Otsu) crocodile, bird, rhinoceros, etc.] (Yasu, and Omi-Hachiman) Konan)

"Sakura Ishi" [Cherry flower stone; "Narutaki Toishi" [Whetstone made of cordierite pseudomorph in metapelite of Miocene molluscan shells in the Tsuzuki 26. Kyoto (Kyoto) Early Triassic siliceous claystone of Tamba belt intruded by Cretaceous Group (Ujitawara) Tamba belt] (Ukyo-ku, Kyoto) granite] (Kameyama)

Alkali Basalt [Pleistocene lava with "Tamba Ryu" [Tambatitanis amicitiae; Chalcopyrite [Akenobe and Ikuno mines magnificent colunmar joints in which Dinosaur discovered from the Lower 27. Hyogo (Kobe) provided copper, silver and tin for Prof. Matuyama first found magnetic Cretaceous Sasayama Group] (Sannan, centuries] (Akenobe Copper Mine) reversal] (Gembudo, Toyooka) Tamba)

"Izumi (Ao-)Ishi" [Sandstone of Late Dawsonite [Carbonate mineral of sodium "Machikane Wani" [Toyotamaphimeia Cretaceous Izumi Group distributed and aluminum that occurs with fossils in machikanensis; Middle Pleistocene 28. Osaka (Osaka) along the Median Tectonic Line; the Izumi Group] (Sennan,Izumi-Sano, crocodile, 7 m long] (Machikane Hills, commonly used for walls and fences] Kaizuka, Kishiwada, etc.) Toyonaka; Osaka University Campus) (Izumi Mts.)

2 Prefecture (Capital) Rock (Place) Mineral (Place) Fossil (Place)

Early Pleistocene terrestrial Basaltic Pillow Lava [formed in ocean Garnet [almandine garnet that occurs as [Teeth and tusks of elephants (Stegodon floor in Triassic and Cretaceous time, and 29. Nara (Nara) phenocrysts of 1 mm size in andesitic to aurorae) and horn of Elaphurus accreted to Japan later] (Mt. Tamaki, dacitic lava] (Nijozan) (elaphuroides) shikamai] (Mami Hills, Kawakami, Yoshino) Koryo and Kawai)

Rhyolitic igneous rocks [lavas, dikes, Sanidine [Potash-rich alkali feldspar 30. Wakayama Cretaceous marine fossils [ammonites, breccias and tuffs of rhyolite] occurring as phenocrysts in Miocene (Wakayama) bivalves and Mosasaurus] (Aritagawa) (Shionomisaki Cape) Kumano rhyolitic rocks] (Taichi)

Dune sand deposits [Tottori sand dune Chromite Ore [Typical podiform chromite that extends for 24 km along the Japan deposits occur among serpentinite Miocene fish [Shallow-water marine fish 31. Tottori (Tottori) Sea coast is fed by granite mountains] bodies of Oeyama ophiolite] (Tari, in the Tottori Group] (Miyashita, Kokufu) (Tottori) Nichinan)

"Mizuho Takobune" [Mizuhobaris "Kimatchi Ishi" [Miocene tuffaceous Native silver [Worldwide major provider izumoensis: Paper Nautilus, a kind of 32. Shimane (Matsue) sandstone used long time for building of silver in the 14-19th Centuries] (Iwami octopods with shell in Miocene age] blocks] (Shinji, Matsue) Silver Mine, Omori, Ota) (Shibuna, Tamayu, Matsue)

Uranium ore [Autunite and ningyoite ores "Mannari Ishi" [Late Cretaceous pink Fossil plants from Nariwa [Late Triassic in Late Miocene conglomerate that was 33. Okayama (Okayama) granite used as building blocks, ginkgos, cykads, pteridophytes, etc.] mined in 1960s] (Ningyotoge Pass, tombstones, etc.] (Okayama) (Nariwa, Takahashi) Kamisaibara, Kagamino)

"Atsu Gaki" [Miocene oyster shells, which Hiroshima granite [Late Cretaceous "Roseki" [Soft rock made of pyrophyllite, occurs associated with whales and 34. Hiroshima (Hiroshima) Granite used as bulding blocks, talc, kaoline, etc. used as refractory sharks, in the Bihoku Group] (Shobara tombstones, etc.] (Hiroshima and vicinity) bricks] (Shokozan, Shobara) and Miyoshi)

Fossil plants from Mine [Triassic ginkgos, Limestone [Carboniferous and Permian 35. Yamaguchi Copper ores [Cretaceous skarn ore] sphenopsids, pteridophytes, etc., limestone forming the largest karst (Yamaguchi) (Nagato Dozan, Akiyoshi) associated with insects; important plateau in Japan] (Akiyoshi) component of high quality coals] (Mine)

Sanukite [Bronzite andesite, glassy high- "Kodai Amamo" [This was thought to be Sillimanite [occurs in the Cretaceous magnesian andesite of Miocene age; its seawead fossil, but recently revealed to 36. Kagawa (Takamatsu) Ryoke metamorphic rocks; mined for piece gives good sound when hit, and be trace fossil] (The Izumi Group producing glass] (Nekoyama, Manno) called "kankan ishi"] (Goshikidai) of Cretaceous age)

Piemontite [Pink to yellow pleochroism is Pterotrigonia [Marine bivalve in the family Blueschist [Cretaceous Sanbagawa basic 37. Tokushima striking under the polarizing microscope; Trigoniidae that serves as an index fossil schist with glaucophane (Na amphibole)] (Tokushima) occurs in Sanbagawa quartz schist] of Mesozoic age] (Kamikatsu and (Bizan and Kotsu, Tokushima) (Bizan, Tokushima) Katsuura)

Syenite [Middle Miocene, potassium and Stronalsite [Sr-bearing feldspar first Silurian marine fossils [Corals (Favosites, sodium-rich, A-type granite with Rapakivi found in serpentinite at Kochi in 38. Kochi (Kochi) Halysites), trilobites, orthoceras, texture, only one in Japan] (Ashizuri association with lawsonite and pectolite] graptolites, etc.] (Mt. Yokokura, Ochi) Cape) (Rendai, Kochi)

Eclogite [Cretaceous Sanbagawa Inoceramus [Age-diagnostic marine Stibnite [World's best crystals (>60 cm metamorphic rock made of omphacite bivalve of Cretaceous age; common in 39. Ehime (Matsuyama) long) at the time the mine was operated] (jadeitic pyroxene) and garnet; formed at the Uwajima and Izumi groups] (Uwajima (Ichinokawa Mine) >60 km depth] (Mt. Higashi Akaishi) and Matsuyama)

Coal [Occurs in Paleogene graben-filling Fossil fish from Wakino [Early Cretaceous sediments; supported industrial Lepidolite [Lithium mica in granitic 40. Fukuoka (Fukuoka) freshwater fish in the Wakino Subgroup] modernization of Japan] (Chikuho coal pegmatite] (Nagataru, Fukuoka) (Kitakyushu, Nogata and Miyawaka) field)

Paleogene fossils from the Karatsu coal Porcelain stone [Pottery stone; altered Beryl [Occurs in pegmatite veins in field [Eocene to Oligocene marine 41. Saga (Saga) from rhyolite lava; made of quartz, Cretaceous granite] (Sugiyama, Fuji, (molluskan shells, sharks, turtles) and sericite, kaoline, etc.] (Arita) Saga) terrestrial (plants, Aminodon (rhinoceras), birds) fossils] (Karatsu, Imari, etc.)

Dacite of Unzen Volcano ["Heisei Shinzan Rock Crystal [Quartz] twinned in Fossil plants from Mogi [Pliocene broad- Lava Dome" formed by 1990-1995 accordance with Japan law [also known leaved deciduous trees (Fagus, Juglans, 42. Nagasaki (Nagasaki) eruption in which a pyroclastic flow as Japanese twin] (Narushima, Goto Carpinus, Zelkova, Liquidambar, Sorbus, resulted in 44 deaths] (Shimabara) Islands) etc.)] (Mogi, Nagasaki)

3 Prefecture (Capital) Rock (Place) Mineral (Place) Fossil (Place)

Obsidian [Pleistocene welded rhyolitic tuff; Obsidian is light colored and Axinite [Boron-bearing skarn mineral Pleistocene freshwater fish [Fossil salmon 43. Oita (Oita) contains rare garnet phenocrysts; used formed by Miocene granite intrusion] and trout in diatomite beds of the Kusu as arrow heads by lithic age people] (Obira Mine, Bungo-Ono) basin] (Nogami, Kuju) (Himeshima Island)

Welded tuff [Locally called "Hai Ishi" (ash Tridymite [Silica mineral with hexagonal Cretaceous dinosaurs [Bones, teeth and 44. Kumamoto stone) and used as building stones by its platy shape of 1 cm size occurring in footprints from Goshoura, Mifune and (Kumamoto) light weight and easy processing] (Aso cavities of andesite] (Mt. Ishigami, Himeura groups] (Amakusa and Mifune) Volcano and vicinity) Shimazaki, Nishi-ku, Kumamoto)

"Oni no Sentaku Iwa" [Devil's washboard Danburite [Calcium-boron silicate Siluro- fossils [Corals (Favosites, rock; inclined Late Miocene turbidites 45. Miyazaki (Miyazaki) occurring as clear crystal of square-pillar Halysites), crinoids, trilobites, etc.] (Mt. that were flat-eroded and uplifted] shape] (Toroku Mine, Takachiho) Gion, Gokase) (Aoshima, Nichinan beach)

"Shirasu" [Ito Pyroclastic Flow Deposits; Gold Ore of Hishikari Mine [Formed by Cretaceous marine fossils [Elasmosaurus, 46. Kagoshima spread all over the prefecture from the Pleistocene (1 Ma) hydrothermal activity; hadrosaurus, pterosaurus, theropods, (Kagoshima) Aira Caldera that erupted ~29,000 year The only one operating metal mine in etc. in the Goshoura and Himeshima ago] (Occur widely) Japan (50 g/t quality)] (Isa) groups] (Shishi Jima and Koshiki Islands)

"Ryukyu Limestone" [Uplifted Pleistocene Phosphorus ore [Guano, a phosphorus "Minatogawa Man" [Late Pleistocene coral reef complex that is used as deposit in limestone, originated from (16-18 ka) Homo sapiens excavated from 47. Okinawa (Naha) building blocks and monuments] (Occurs organic excrement of seabirds] (Oki a fissure in the "Ryukyu Limestone"] widely) Daito and Kita Daito Islands) (Nagamo, Yaese)

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