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Giant Stibnite Crystals from the Ichinokawa Mine, Japan

Source : Mineralogisches Institut Hamburg


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Stibnite - Antimonit - Stibnite - Antimonita

Asia : Japan : Stibnite / Antimonite crystals up to 1 m from the Ichinokawa Mine

Coordinates : 33°53'N , 133°12'E : Ichinokawa mine, Saijo, Ehime Prefecture, Shikoku Island, Japan

This is one of the famous "classic" giant crystal localities, well known to many mineralogists, geologists and collectors alike since almost 200 years and well represented with superb specimens in many collections worldwide. Emphazising this, remarkable little detailed mineralogical work has been done on this locality, at least not much has been published in readily acessible western journals.

The Ichinokawa mine supplied the largest known stibnite / antimonite crystals of the world, outranging easily any other deposit. The crystals reach at least 0,6 m in length, possibly even 1 m or more and though similiar long stibnite crystals were recently discovered in China, the classic Ichinokawa stibnites are of a much stouter and bulkier appearance. They also show a great diversity of crystal forms and therefore thrilled the early crystallographers, who described not less than 100 different forms from these crystals.

Antimony mineralization at Ichinokawa is controlled by a major tertiary fault system, separating cretaceous sandstones and shales from permo - triassic slates, phyllites and schists. The mineralizazion itself is simple, mainly consisting out of quartz veins and antimonite with ocassional other sulphides. Mining at Ichinokawa started before 1780 and large vugs with plenty of stibnite crystals were discovered soon. As a local tale goes, large crystals of stibnite were so bountiful and easy to collect, that the miners simply used the large crystal logs to fence off their premises !

Most of the crystals displayed today were mined between 1882 and 1886 and were sold to many private collectors and museums worldwide. Some of the best of the remaining crystals are now located in the german mineral museums in Freiberg and Hamburg as well as in the Smithsonian Insitution in the USA. Only few major crystals remained in Japan with the famous Wada collection - bought by the Mitsubishi Metal Mining Co. - being probably the best Ichinokawa stibnite collections around. Another 1 m sized stibnite crystal is said to be located in the Mineral Department of Tokyo university.

Mining in Ichinokawa ceased in 1910 and though some exploration work took place in the 1950ies, the mine was never reopened. The voluminous mine dumps, which can be seen on historic photos, are still there and may still host many finds of nice stibnite specimen, though surely no giant ones.

Update March 2006 : We just got the information, that the Wada collection with its giant stibnites is on display in the Ikuno Mine and Mineral Museum at 33-5 Aza-Otani-Suji, Ono, Ikuno-Cho, Asago-Shi, Hyogo-Ken, 6793324, Japan.



The Ichinokawa stibnite in a nutshell :

Mineralogy :

Stibnite / Antimonite and minor other sulphides

Crystal Size :

Crystal size up to 0,6 m confirmed, but larger crystals up to 1 m have been reported

Geology & Formation

Epithermal formation from hydrothermal fluids in major tectonic shear zone

Current status :

Abandoned mine, no major stibnite finds since several decades

Remarks :

A classical giant crystal locality, well known to many early geoscientists




Other notable & famous antimonite / stibnite occurences :

Note : Stibnite / Antimonite - an antimony sulphide with the formula Sb2S3 - is frequently confused with native antimony, the element Sb. Whereas even large Stibnite crystals are common, the native element Sb only very rarely show well developed crystals.

- Recent finds of caves filled with highly lustrous stibnite crystal clusters are reported from various mines in China. These crystals may reach up to 1 m size or weven more. A spectacular group of these stibnite crystals was on display at the Munich Mineral fair 2004 and you can see it here.

- Classic localities of large and excellent groups of stibnite crystals up to 20 cm are located within Romania, namely in Baia Sprie and Herja.

- A little known mine at Kostajna, Serbia, produced individual stibnite crystals to 1 m size and accordingly is among the localities with the largest stibnite crystals.

- Large Hg - Sb deposits with acicular stibnite crystals up to 25 cm length occur at Kalamdzhay, Alai Mountains, Kyrgyzistan.

- Another notable stibnite mine, reputedly to be once the largest Sb - mine in in the world, is La Lucette, Mayenne department, France, where stibnite crystals up to 20 cm size occur.



Wada Collection, Japan : 60 cm long stibnite crystal from Ichinokawa

Source : Mitsubishi Mining, Wada Collection


Historical photo : Plant and dumps at Ichinokawa, ca. 1890

Source : P.BANCROFT (1984) : Gem & Crystal Treasures



Resources and relevant weblinks :

For more information on the mineral stibnite / antimonite please look at, Webmineral and the german Mineralienatlas.

The most comprehensive infomation about the mine and its giant stibnites can be found in BANCROFT, P. (1984) : Gem & Crystal Treasures. Representative samples of Ichinokawa stibnites are on display in many mineralogical collections of the world, namely the Wada Collection, now housed in the Ikuno mine and mineral museum, and the museums in Freiberg and Hamburg, both Germany.




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