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The large Dalnegorsk ore field in the Primorskiy Kraj district, Far East Russia with numerous major ore depsoits is a real treasure trove for geologists, mineralogists and mineral collectors alike. There are two completely different paragenesis present at Dalnegorsk :
- Complex skarn type mineralizsation with a large variety of sulphide minerals like excellent pyrrhotite crystals up to at least 30 cm and not much smaller crystals of the ore minerals chalcopyrite, galena and sphalerite. Another typical and often perfectly crystallized mineral is ilvaite, which occurs in splendid and lustrous black crystals up to 10 cm and more. And then there is calcite, which is also reported in a multitude of different shapes and in sizes up to one meter !. Even more eye - appealling are fluorite crystals in a large variety of different colours and sizes. Some of these fluorite crystals are absolutely clear and colourless and sometimes appear to be just "crystallized water"...
At the direct contact between igneous rocks and limestone a peculiar hedenbergite - wollastonite rock is present in large quantities with radiating hedenbergite crystal clusters, which often may reach diameters of 1 m and more.
- Apart from the polymetallic sulphide ore bodies there is a second, even more unusual mineral assemblage present in the "Borosilikatnoye deposit". Huge resources of borosilicates occur, predominantly composed of the minerals danburite and datolite. These borosilicates - sometimes accompanied by sulphides and a suite of rare native elements : antimony, arsenic and bismuth - often form beautiful crystals and mineral specimens, which may reach considerable sizes. The boron silicates are of major economic importance and one of the few mineable boron occurences in Russia.
Speaking of giant crystals, Dalnegorsk host a variety of different species in remarkable sizes. Peculiar vents develop in the sulphide orebodies and host large calcite crystals up to 1 m size, which often show a distinct hexagonal habitus as shown in the photo. Perfectly crystallized fluorite crystals may reach several decimeter with at least one documented case of a 1 m sized single fluorite cube (!) which "rolled out of a vug" some years ago. Nothing is known about its further fate of this crystal at this stage, but if you know anything, please tell us. Equally sulpide crystals may reach eceptional sizes of several decimeter, such as pyrrhotite and chalcopyrite crystals.
The very common hedenbergite crystals at the outer rims of the ore bodies often form giant spheres along the limestone contact. Wollastonite aggregates may reach similiar sizes. The most peculiar "giant crystal aggregates" of the lot may well be the Dannemorite. This mineral is only found in open cavities between spherical hedenbergite aggregates. In the Verkhneye deposit dannemorite forms up to several squaremeters (!) large thin aggregates of small to minute crystals resembling leather window - clothes ! A prime example of this very peculiar mineral is exhibited in the Fersman Mineralogical Museum, as documented in the photo.
Though the Dalnegorsk mining district have alreay yielded a large and varied suite of giant crystals, the author feels, that there might be much more to be explorend and documented in this astonishing area in terms of unsusual giant crystals...
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The Dalnegorsk ore field in a nutshell :
Mineralogy : |
Complex sulphide & calc silicate deposits, sometimes rich in boron silicates |
Crystal Size : |
Crystals of hedenbergite, calcite and fluorite (and possibly Danburite and Datolite ?) may all reach sizes of up to 1 m (confirmed). There are also giant, leather like aggregates of dannemorite, which may cover several square meters ! |
Geology & Formation |
Complex skarn type mineralizationm, rich in sulphides and boron
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Current status : |
Ongoing mining activity in both the sulphide and boron deposits |
Remarks : |
Mineralogically extremely rich with splendid and large mineral specimen. Easily one of the most spectacular mining districts both in terms of mineralogy and geology.
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Other notable & famous fluorite occurences :
Note : For other giant calcite occurences please click here, here and also here.
Further note : Fluorite is a common mineral and many localities and mines in many countries have provided excellent specimen of this mineral up to considerable crystal sizes. Please find below only localiies with exceptional large crystals.
- The probably largest recorded fluorite crystals are of pegmatitic origins and occur in the Globe Mine, Petaca District, New Mexico, USA. They may reach a size of up to 2 m, but do show only very rough crystal faces.
- Cubes to 30 cm are reported from the Menhenioth mining district, Cornwall, Great Britain and even larger ones from Rottleberode mine, Harz Mountains, Germany
- Hydrothermal quartz - fluorite veins in the Tarn Department, France, produced cubes up to 1 m size, whereas similiar large cubes were reported from the Moldava deposit, Krusne Hory in the Czech Republic.
- Superb violet fluorite cubes up to 50 cm and more are known in abundance from the Elmwood mine, Tennesse, USA.
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Other notable & famous dannemorite / manganogrunerite occurences :
Note : Dannemorite is an obsolete (though still much used) mineral name, the mineral is now called manganogrunerite. It is one of the minerals of the asbestiform minerals, i.e it generally forms fibrous to acicular crysals, which may reach several decimeter length or even more. Well developed crystals are rare.
- Common in the Mn-Skarn at Dannemora, Sweden, where Dannemorite forms prismatic crystals up to 15 cm.
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Other notable & famous hedenbergite occurences :
Note : Hedenbergite is a mineral, which rarely forms well defined crystals, but rather radiating or fibrous masses. It is a typical skarn mineral, which forms along the contact zone of igneous rocks to limestones.
- The Elba island / Italy is a locality, where large radiating clusters up to several decimeters are found along with black ilvaite.
- Very similiar is the hedenbergite occurence on the greek island of Serifos, where radiating hedenbergite sprays are associated with ilvaite and often showy green praseme crystals, a quartz variety.
- Well crystallized hedenbergite up to several centimeter size is known from some localities such as the Skardu valley, Pakistan and the Broken Hill deposit, Australia.
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Large calcite crystals in a "vent" typically for the sulphide ore bodies at Dalnegorsk
Source : V. Chernavtev archive, from Mineralogical Almanac, Vol. 4 / 2001 - see reference below
Schematic sketch of giant hedenbergite spheres, interlayered with sulphide bands
Source : Drawing by : Radkevich et. al. (1960), from Mineralogical Almanac, Vol. 4 / 2001
see reference below
Dannemorite - "leather cloth", 1,65 x 1,10 m large, shown in the Fersman Mineralogical museum
Source : Photo taken by M. Leybov, from Mineralogical Almanac, Vol. 4 / 2001
see reference below
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Resources and relevant weblinks :
The most comprehensive english infomation about the Dalnegorsk ore field is :
MOROSHKIN, V.V. & FRISHMAN; N.L. (2001) : Dalnegorsk : Notes on Mineralogy,- Mineralogical Almanac - Russian Mineral Locality Series, Vol. 4 / 2001, pp. 136, published by Ocean Pictures, Moscow 2001.
Some - often only basic and sketchy - information about Dalnegorsk is contained in various papers in europoean mineralogical magazins like Lapis, Mineralienwelt (both german) and others, but much of the more detailed publications are only available in russian language.
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