Charoite - K5Ca8(Si6O15)2(Si2O7)Si4O9(OH)*3(H2O)

Charoite is a unique mineral called "the lilac miracle of Siberia" and It is considered "the main mineralogical discovery of the second half of the 20th century". Charoite was discovered in 1949 and confirmed as a new mineral species in 1977. According to the discoverers of the mineral, the name originates from the Chara River, situated close to the southem border of the Murun complex. An "unofficial" hypothesis suggests the Russian word “charovat” (to charm) as a possible origin for the name. It has been found at only one locality in at the broad contact aureole of the Early Cretaceous Malyy Murun syenite massif, northwestern Aldan Shield of the Siberian Craton (Fig.1).

Optical Properties:
Form: Massive to Fibrous.
Color: Colorless.
Pleochroism: Weak (from rose to colorless).
Relief: Low.
Interference colors: Low (I order white-gray).

Murun Complex

Mesozoic K-alkaline intrusions are abundant at the Aldan shield and they are distributed in the northern part with a strike roughly parallel to the NE-SW trending Mongolia-Okhotsk orogenic belt (Fig.2). This orogenic belt is a reflection of subduction of the Mongolia-Okhotsk oceanic plate. The Mongolia-Okhotsk Ocean closed at the Carboniferous in the west and in the Late Cretaceous in the east.

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Fig.1: Malyy Murun syenite massif location map.



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Fig.2: Tectonic sketch map of Mesozoic Siberia and East Asia. Arrows show time when particular parts of the Mongolia-Okhotsk Ocean closed. After Kostyuk et al. (1990).



By the time of magmatism at the Malyy Murun, the Mongolia-Okhotsk subduction ceased at the central part of the orogenic belt and thus Early Cretaceous magmatism at the Malyy Murun massif represents a post-subduction process, which was coeval to rifting at the central part of the Mongolia-Okhotsk orogenic belt. The Malyy Murun massif (ca.48 km2) is a part of a larger Murun ultrapotassic complex (150-180 Km2), which consists of the Bolshoy (Great) Murun, Malyy (Little) Murun, and Dagaldyn massifs (Fig 3). The Malyy Murun and Dagaldyn massifs are Early Cretaceous and Early Jurassic, respectively. The Bolshoy Murun massif is not yet dated. The northern part of the Malyy Murun syenite massif is bounded by skarns at the contact with the carbonate wall rocks. The southern part of the massif is bounded by quartz sandstones, where a broad contact aureole of fenites developed. All known outcrops of charoitite rocks were found within fenites.

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Fig.3: Geologic map of the Murun ultrapotassic complex and a cross-section at the Stary prospecting site. After Vorobyev (2008).



The complex was discovered in the late 1930-s - early 1940-s by the VG Ditmar expedition. Since then, dozens of scientists have been involved in the geological exploration of Murun. As this exploration progressed, the complexity of the geological and tectonic situation at Murun became increasingly evident. The Murun complex is, perhaps, best known for a suite of Ca-rich fenitic rocks developed from the Proterozoic carbonaceous sandstones. Beginning in the 1960-s, a number of new minerals of unusual composition and structure have been discovered in the fenites. Many of these, including frankamenite and the gemstone charoite, are quite common in the Murun rocks, but have not been encountered anywhere else in the world.
There is no agreement between geologists as to what the composition of the parental magma was, or how the intrusions developed in time, or regarding genetic relationships between the individual petrographic series.

At present, there are two major views on the evolution of the Murun complex:

1) Orlova et al. (1987, 1988) suggest that the complex developed as a single layered lopolith by magmatic differentiation.
2) Ivanyuk & Evdokimov (1991), Mitchell & Vladykin (1996), Konev et al. (1996), (Vladykin, 2000) and others suggests that the individual intrusive phases were emplaced independently as a series of plutonic and hypabyssal bodies. They recognized four magmatic stages in the Malyi Murun Massif:

Early phase: makes up the northeastern part of the massif. It includes the following rocks: (1) Cumulate formations: olivine-spinel rock seggregations with zones of melilite-bearing olivinepyroxene-phlogopite-monticellite rocks, which occur as xenoliths in biotite pyroxenites. (2) Layered complex of ultrabasic ultrapotassic rocks composed of Biotite-pyroxenites, olivine, K-ijolites, leucitic fergusites, and shonkinites.

Major phase: occupies the central part of the massif. It is made up of a horizontally, layered units of various pseudoleucitic, kalsilitic, and biotite-pyroxene-bearing K-feldspathic syenites, whose crystallization terminated in the formation of quartz syenites and dykes and stocks of alkali granites. The pseudoleucitic syenites (synnyrites) in the northeast of the massif form a large body not less than 600 m in thickness.

Volcanic phase: comprises the central and northern parts of the massif. This is a layered flow of leucitic melaphonolites, leucitites, and leucitic lamproites (minette) with zones of tuff breccias. The dyke complex of this phase is formed by leucitic tinguaites, richterite-sanidine lamproites, trachyte-porphyries and syenite-porphyries.

Late phase: It occupies the southeastern part of the massif, covering 10 km2, and is made up of banded layered complex of potassic silicate-carbonate rocks which form 1 to 20-30 m wide bands. These bands are: (1) white microgranular K-feldspathic rocks consisting of K-feldspar with minor admixtures of pyroxene and tinaksite; (2) quartz-calcite-pyroxene-microcline rocks with calcite contents varying from 5 to 20%; (3) pyroxene-K-feldspathic rocks with widely varying contents of both components.
The rocks have diverse structures and textures: banded, spherolitic (for pyroxene), equigranular, fine- and coarse-grained, etc.; (4) essentially pyroxene rocks. This layered banded outcrop contains carbonatites and charoite rocks, which are represented by veins, dykes, and some sill-like formations having no sharp contacts with the silicate-carbonate rocks.



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Purple flaky and massive charoite crystals associated with tan colored tinaksite. Murun Massif, Aldan Shield, Yakutia, Russia. From RRUFF.




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Purple flaky and massive charoite crystals. Murun Massif, Aldan Shield, Yakutia, Russia. From RRUFF.




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Purple flaky and massive charoite crystals, black aegirine and yellow tinaksite. Murun Massif, Aldan Shield, Yakutia, Russia. From RRUFF.




Bibliography



• Mitchell, R. H., & Vladykin, N. V. (1996). Compositional variation of pyroxene and mica from the Little Murun ultrapotassic complex, Aldan Shield, Russia. Mineralogical Magazine, 60(6), 907-925.
• Reguir, E. (2002). Aspects of the Mineralogy of the Muran Alkaline Complex, Yakutia, Russia. National Library of Canada. Bibliothèque nationale du Canada.
• Vladykin, N. V., Viladkar, S. G., Miyazaki, T., & Mohan, V. R. (2008). Geochemistry of Benstonite and Associated Carbonatites of Sevathur, Jogipatti and Samalpatti, Tamil Nadu, South India and Murun Massif, Siberia. Journal of the Geological Society of India, 72(3), 312-324.
• Vladykin, N. V. (2009). Potassium alkaline lamproite–carbonatite complexes: petrology. Genesis, and their reserves, Russ. Geol. Geophys, 50(12), 1443-1455.
• Wang, Y., He, H., Ivanov, A. V., Zhu, R., & Lo, C. (2014). Age and origin of charoitite, Malyy Murun massif, Siberia, Russia. International Geology Review, 56(8), 1007-1019.

Photo
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Fibrous charoite (beige color) and green aegirine crystals in a charoitite. Murun Massif, Aldan Shield, Yakutia, Russia. PPL image, 1x (Field of view = 9mm)
charoite(2).jpg

Fibrous charoite (I order gray) and aegirine (high interference colors) crystals in a charoitite. Murun Massif, Aldan Shield, Yakutia, Russia. XPL image, 1x (Field of view = 9mm)
charoite(3).jpg

Fibrous charoite (beige color) and green aegirine crystals in a charoitite. Murun Massif, Aldan Shield, Yakutia, Russia. PPL image, 1x (Field of view = 9mm)
charoite(4).jpg

Fibrous charoite (I order gray) and aegirine (high interference colors) crystals in a charoitite. Murun Massif, Aldan Shield, Yakutia, Russia. XPL image, 1x (Field of view = 9mm)
charoite(5).jpg

Fibrous charoite (beige color) and green aegirine crystals in a charoitite. Murun Massif, Aldan Shield, Yakutia, Russia. PPL image, 1x (Field of view = 9mm)
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Fibrous charoite (I order gray) and aegirine (high interference colors) crystals in a charoitite. Murun Massif, Aldan Shield, Yakutia, Russia. XPL image, 1x (Field of view = 9mm)
charoite(9).jpg

Fibrous charoite (beige color) and green aegirine crystals in a charoitite. Murun Massif, Aldan Shield, Yakutia, Russia. PPL image, 1x (Field of view = 9mm)
charoite(10).jpg

Fibrous charoite (I order gray) and aegirine (high interference colors) crystals in a charoitite. Murun Massif, Aldan Shield, Yakutia, Russia. XPL image, 1x (Field of view = 9mm)
charoite(11).jpg

Fibrous charoite (beige color) and green aegirine crystals in a charoitite. Murun Massif, Aldan Shield, Yakutia, Russia. PPL image, 1x (Field of view = 9mm)
charoite(15).jpg

Fibrous charoite (I order gray) and aegirine (high interference colors) crystals in a charoitite. Murun Massif, Aldan Shield, Yakutia, Russia. XPL image, 1x (Field of view = 9mm)
charoite(16).jpg

Fibrous charoite (I order gray) and aegirine (high interference colors) crystals in a charoitite. Murun Massif, Aldan Shield, Yakutia, Russia. XPL image, 1x (Field of view = 9mm)
charoite(17).jpg

Fibrous charoite (I order gray) and aegirine (high interference colors) crystals in a charoitite. Murun Massif, Aldan Shield, Yakutia, Russia. XPL image, 1x (Field of view = 9mm)
charoite(18).jpg

Fibrous charoite (I order gray) and aegirine (high interference colors) crystals in a charoitite. Murun Massif, Aldan Shield, Yakutia, Russia. XPL image, 1x (Field of view = 9mm)
charoite(20).jpg

Fibrous charoite (I order gray) and aegirine (high interference colors) crystals in a charoitite. Murun Massif, Aldan Shield, Yakutia, Russia. XPL image, 1x (Field of view = 9mm)
charoite(21).jpg

Fibrous charoite (I order gray) and aegirine (high interference colors) crystals in a charoitite. Murun Massif, Aldan Shield, Yakutia, Russia. XPL image, 1x (Field of view = 9mm)
charoite(23).jpg

Fibrous charoite (I order gray) and aegirine (high interference colors) crystals in a charoitite. Murun Massif, Aldan Shield, Yakutia, Russia. XPL image, 1x (Field of view = 9mm)
charoite(24).jpg

Fibrous charoite (beige color) and green aegirine crystals in a charoitite. Murun Massif, Aldan Shield, Yakutia, Russia. PPL image, 1x (Field of view = 9mm)
charoite(25).jpg

Fibrous charoite (I order gray) and aegirine (high interference colors) crystals in a charoitite. Murun Massif, Aldan Shield, Yakutia, Russia. XPL image, 1x (Field of view = 9mm)
charoite(26).jpg

Fibrous charoite (beige color) and green aegirine crystals in a charoitite. Murun Massif, Aldan Shield, Yakutia, Russia. PPL image, 2x (Field of view = 7mm)
charoite(27).jpg

Fibrous charoite (I order gray) and aegirine (high interference colors) crystals in a charoitite. Murun Massif, Aldan Shield, Yakutia, Russia. XPL image, 2x (Field of view = 7mm)
charoite(28).jpg

Fibrous charoite (beige color) and green aegirine crystals in a charoitite. Murun Massif, Aldan Shield, Yakutia, Russia. PPL image, 2x (Field of view = 7mm)
charoite(29).jpg

Fibrous charoite (I order gray) and aegirine (high interference colors) crystals in a charoitite. Murun Massif, Aldan Shield, Yakutia, Russia. XPL image, 2x (Field of view = 7mm)
charoite(30).jpg

Fibrous charoite (beige color) and green aegirine crystals in a charoitite. Murun Massif, Aldan Shield, Yakutia, Russia. PPL image, 2x (Field of view = 7mm)
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Fibrous charoite (beige color) and green aegirine crystals in a charoitite. Murun Massif, Aldan Shield, Yakutia, Russia. PPL image, 2x (Field of view = 7mm)
charoite(33).jpg

Fibrous charoite (I order gray) and aegirine (high interference colors) crystals in a charoitite. Murun Massif, Aldan Shield, Yakutia, Russia. XPL image, 2x (Field of view = 7mm)
charoite(34).jpg

Fibrous charoite (beige color) and green aegirine crystals in a charoitite. Murun Massif, Aldan Shield, Yakutia, Russia. PPL image, 2x (Field of view = 7mm)
charoite(35).jpg

Fibrous charoite (I order gray) and aegirine (high interference colors) crystals in a charoitite. Murun Massif, Aldan Shield, Yakutia, Russia. XPL image, 2x (Field of view = 7mm)
charoite(36).jpg

Fibrous charoite (I order gray) and aegirine (high interference colors) crystals in a charoitite. Murun Massif, Aldan Shield, Yakutia, Russia. XPL image, 2x (Field of view = 7mm)
charoite(39).jpg

Fibrous charoite (I order gray) and aegirine (high interference colors) crystals in a charoitite. Murun Massif, Aldan Shield, Yakutia, Russia. XPL image, 2x (Field of view = 7mm)
charoite(41).jpg

Fibrous charoite (I order gray) and aegirine (high interference colors) crystals in a charoitite. Murun Massif, Aldan Shield, Yakutia, Russia. XPL image, 2x (Field of view = 7mm)
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Fibrous charoite (I order gray) crystals in a charoitite. Murun Massif, Aldan Shield, Yakutia, Russia. XPL image, 10x (Field of view = 2mm)
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Fibrous charoite (I order gray) crystals in a charoitite. Murun Massif, Aldan Shield, Yakutia, Russia. XPL image, 10x (Field of view = 2mm)
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Fibrous charoite (I order gray) and aegirine (high interference colors) crystals in a charoitite. Murun Massif, Aldan Shield, Yakutia, Russia. XPL image, 10x (Field of view = 2mm)
charoite(60).jpg

Fibrous charoite (beige color) and green aegirine crystals in a charoitite. Murun Massif, Aldan Shield, Yakutia, Russia. PPL image, 10x (Field of view = 2mm)
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Fibrous charoite (I order gray) and aegirine (high interference colors) crystals in a charoitite. Murun Massif, Aldan Shield, Yakutia, Russia. XPL image, 10x (Field of view = 2mm)
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Fibrous charoite (I order gray) and aegirine (high interference colors) crystals in a charoitite. Murun Massif, Aldan Shield, Yakutia, Russia. XPL image, 10x (Field of view = 2mm)
charoite(63).jpg

Fibrous charoite (beige color) and green aegirine crystals in a charoitite. Murun Massif, Aldan Shield, Yakutia, Russia. PPL image, 10x (Field of view = 2mm)
charoite(64).jpg

Fibrous charoite (I order gray) and aegirine (high interference colors) crystals in a charoitite. Murun Massif, Aldan Shield, Yakutia, Russia. XPL image, 10x (Field of view = 2mm)
charoite(65).jpg

Fibrous charoite (beige color) and green aegirine crystals in a charoitite. Murun Massif, Aldan Shield, Yakutia, Russia. PPL image, 10x (Field of view = 2mm)
charoite(66).jpg

Fibrous charoite (I order gray) and aegirine (high interference colors) crystals in a charoitite. Murun Massif, Aldan Shield, Yakutia, Russia. XPL image, 10x (Field of view = 2mm)
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Fibrous charoite (beige color) and green aegirine crystals in a charoitite. Murun Massif, Aldan Shield, Yakutia, Russia. PPL image, 10x (Field of view = 2mm)
charoite(68).jpg

Fibrous charoite (I order gray) and aegirine (high interference colors) crystals in a charoitite. Murun Massif, Aldan Shield, Yakutia, Russia. XPL image, 10x (Field of view = 2mm)
charoite(69).jpg

Fibrous charoite (beige color), quartz (colorless) and green aegirine crystals in a charoitite. Murun Massif, Aldan Shield, Yakutia, Russia. PPL image, 10x (Field of view = 2mm)
charoite(70).jpg

Fibrous charoite (I order gray), quartz (I order gray-white) and aegirine (high interference colors) crystals in a charoitite. Murun Massif, Aldan Shield, Yakutia, Russia. XPL image, 10x (Field of view = 2mm)
charoite(71).jpg

Fibrous charoite (beige color), quartz (colorless) and green aegirine crystals in a charoitite. Murun Massif, Aldan Shield, Yakutia, Russia. PPL image, 10x (Field of view = 2mm)
charoite(92).jpg

Fibrous charoite (beige color) and quartz (colorless) crystals in a charoitite. Murun Massif, Aldan Shield, Yakutia, Russia. PPL image, 10x (Field of view = 2mm)
charoite(93).jpg

Fibrous charoite (I order gray) and quartz (I order gray-white) crystals in a charoitite. Murun Massif, Aldan Shield, Yakutia, Russia. XPL image, 10x (Field of view = 2mm)
charoite(97).jpg

Fibrous charoite (beige color) and quartz (colorless) crystals in a charoitite. Murun Massif, Aldan Shield, Yakutia, Russia. PPL image, 10x (Field of view = 2mm)
charoite(115).jpg

Fibrous charoite (beige color) and quartz (colorless) crystals in a charoitite. Murun Massif, Aldan Shield, Yakutia, Russia. PPL image, 10x (Field of view = 2mm)
charoite(116).jpg

Fibrous charoite (I order gray) and quartz (I order gray-white) crystals in a charoitite. Murun Massif, Aldan Shield, Yakutia, Russia. XPL image, 10x (Field of view = 2mm)
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Fibrous charoite (beige color) and quartz (colorless) crystals in a charoitite. Murun Massif, Aldan Shield, Yakutia, Russia. PPL image, 10x (Field of view = 2mm)
charoite(76).jpg

Fibrous charoite (beige color), quartz (colorless) and green aegirine crystals in a charoitite. Murun Massif, Aldan Shield, Yakutia, Russia. PPL image, 10x (Field of view = 2mm)
charoite(78).jpg

Fibrous charoite (beige color), quartz (colorless) and green aegirine crystals in a charoitite. Murun Massif, Aldan Shield, Yakutia, Russia. PPL image, 10x (Field of view = 2mm)
charoite(79).jpg

Fibrous charoite (beige color), quartz (colorless) and green aegirine crystals in a charoitite. Murun Massif, Aldan Shield, Yakutia, Russia. PPL image, 10x (Field of view = 2mm)
charoite(80).jpg

Fibrous charoite (I order gray), quartz (I order gray-white) and aegirine (high interference colors) crystals in a charoitite. Murun Massif, Aldan Shield, Yakutia, Russia. XPL image, 10x (Field of view = 2mm)
charoite(82).jpg

Fibrous charoite (I order gray), quartz (I order gray-white) and aegirine (high interference colors) crystals in a charoitite. Murun Massif, Aldan Shield, Yakutia, Russia. XPL image, 10x (Field of view = 2mm)
charoite(83).jpg

Fibrous charoite (I order gray), quartz (I order gray-white) and aegirine (high interference colors) crystals in a charoitite. Murun Massif, Aldan Shield, Yakutia, Russia. XPL image, 10x (Field of view = 2mm)
charoite(86).jpg

Fibrous charoite (I order gray), quartz (I order gray-white) and aegirine (high interference colors) crystals in a charoitite. Murun Massif, Aldan Shield, Yakutia, Russia. XPL image, 10x (Field of view = 2mm)
charoite(90).jpg

Fibrous charoite (beige color), quartz (colorless) and green aegirine crystals in a charoitite. Murun Massif, Aldan Shield, Yakutia, Russia. PPL image, 10x (Field of view = 2mm)
charoite(91).jpg

Fibrous charoite (I order gray), quartz (I order gray-white) and aegirine (high interference colors) crystals in a charoitite. Murun Massif, Aldan Shield, Yakutia, Russia. XPL image, 10x (Field of view = 2mm)
charoite(130).jpg

Fibrous charoite (I order gray), quartz (I order gray-white) and aegirine (high interference colors) crystals in a charoitite. Murun Massif, Aldan Shield, Yakutia, Russia. XPL image, 10x (Field of view = 2mm)
charoite(138).jpg

Fibrous charoite (I order gray), quartz (I order gray-white) and aegirine (high interference colors) crystals in a charoitite. Murun Massif, Aldan Shield, Yakutia, Russia. XPL image, 10x (Field of view = 2mm)
charoite(141).jpg

Fibrous charoite (I order gray), quartz (I order gray-white) and aegirine (high interference colors) crystals in a charoitite. Murun Massif, Aldan Shield, Yakutia, Russia. XPL image, 10x (Field of view = 2mm)
charoite(145).jpg

Fibrous charoite (I order gray), quartz (I order gray-white) and aegirine (high interference colors) crystals in a charoitite. Murun Massif, Aldan Shield, Yakutia, Russia. XPL image, 10x (Field of view = 2mm)
charoite(146).jpg

Fibrous charoite (I order gray), quartz (I order gray-white) and aegirine (high interference colors) crystals in a charoitite. Murun Massif, Aldan Shield, Yakutia, Russia. XPL image, 10x (Field of view = 2mm)
charoite(148).jpg

Fibrous charoite (I order gray), quartz (I order gray-white) and aegirine (high interference colors) crystals in a charoitite. Murun Massif, Aldan Shield, Yakutia, Russia. XPL image, 10x (Field of view = 2mm)
charoite(150).jpg

Fibrous charoite (I order gray), quartz (I order gray-white) and aegirine (high interference colors) crystals in a charoitite. Murun Massif, Aldan Shield, Yakutia, Russia. XPL image, 10x (Field of view = 2mm)
charoite(151).jpg

Fibrous charoite (I order gray), quartz (I order gray-white) and aegirine (high interference colors) crystals in a charoitite. Murun Massif, Aldan Shield, Yakutia, Russia. XPL image, 10x (Field of view = 2mm)
charoite(152).jpg

Fibrous charoite (I order gray), quartz (I order gray-white) and aegirine (high interference colors) crystals in a charoitite. Murun Massif, Aldan Shield, Yakutia, Russia. XPL image, 10x (Field of view = 2mm)
charoite(84).jpg

Fibrous charoite (I order gray) crystals in a charoitite. Murun Massif, Aldan Shield, Yakutia, Russia. XPL image, 10x (Field of view = 2mm)
charoite(104).jpg

Fibrous charoite (I order gray) crystals in a charoitite. Murun Massif, Aldan Shield, Yakutia, Russia. XPL image, 10x (Field of view = 2mm)
charoite(108).jpg

Fibrous charoite (I order gray) crystals in a charoitite. Murun Massif, Aldan Shield, Yakutia, Russia. XPL image, 10x (Field of view = 2mm)
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Fibrous charoite (I order gray) crystals in a charoitite. Murun Massif, Aldan Shield, Yakutia, Russia. XPL image, 10x (Field of view = 2mm)
charoite(131).jpg

Fibrous charoite (I order gray) crystals in a charoitite. Murun Massif, Aldan Shield, Yakutia, Russia. XPL image, 10x (Field of view = 2mm)
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Fibrous charoite (I order gray) crystals in a charoitite. Murun Massif, Aldan Shield, Yakutia, Russia. XPL image, 10x (Field of view = 2mm)