Sudoite

Sudoite
Sudoite
General
Category	Chlorite_group
Formula; (repeating unit)	Mg2Al3(Si3Al)O10(OH)8
Crystal system	Monoclinic
Identification
Color	White to light green
Mohs scale hardness	2.5–3.5
Luster	pearly, dull
Refractive index	nα = 1.581 à 1.583; nβ = 1.584 à 1.589; nγ = 1.591 à 1.601
Birefringence	biaxial (-) ; δ = 0.010 to 0.018; 2V = 64 to 70° (measured); 2V = 68 to 72° (calculated)
References

Sudoite is a mineral from the chlorite group. It was named after Toshio Sudo (1911-2000), professor of mineralogy at the University of Tokyo, in Japan, and a pioneer of clay science.^[3] The mineral tosudite also bears his name. It was approved as a valid species by the International Mineralogical Association in 1966.

Characteristics

Sudoite is a clay mineral with chemical formula defined as Mg₂Al₃(Si₃Al)O₁₀(OH)₈. It has a monoclinic crystal system. Its hardness on the Mohs scale is between 2.5 and 3.5.

Classification

Following the Nickel–Strunz classification, it is contained in the "09.EC.55" group:

Members of the 9.EC.55 group
Mineral	Formula	Symmetry group	Space group
Baileychlore	(Zn,Al) ₃[Fe ₂Al][Si ₃AlO ₁₀](OH) ₈	1 or 1	C1 or C1
Borocookeite	Li _1+3xAl _4-x(BSi ₃)O ₁₀(OH,F) ₈ (x ≤ 0,33)	2/m	C2/m
Chamosite	(Fe,Mg,Fe) ₅Al(Si ₃Al)O ₁₀(OH,O) ₈	2/m	C2/m
Clinochlore	(Mg,Fe) ₅Al(Si ₃Al)O ₁₀(OH) ₈	2/m	C2/m
Cookeite	LiAl ₄(Si ₃Al)O ₁₀(OH) ₈	1, 2 or 2/m	C1, C2 or Cc
Donbassite	Al ₂[Al _2,33][Si ₃AlO ₁₀](OH) ₈	2/m	C2/m
Franklinfurnaceite	Ca(Fe,Al)Mn ₄Zn ₂Si ₂O ₁₀(OH) ₈	2	C2
Glagolevite	NaMg ₆[Si ₃AlO ₁₀](OH,O) ₈·H ₂O	1	C1
Gonyerite	Mn ₃[Mn ₃Fe][(Si,Fe) ₄O ₁₀](OH,O) ₈		unknown
Nimite	(Ni,Mg,Fe) ₅Al(Si ₃Al)O ₁₀(OH) ₈	2/m	C2/m
Odinite	(Fe,Mg,Al,Fe,Ti,Mn) _2,5(Si,Al) ₂O ₅(OH) ₄	m	Cm
Orthochamosite	(Fe,Mg,Fe) ₅Al(Si ₃Al)O ₁₀(OH,O) ₈		unknown
Pennantite	Mn ₅Al(Si ₃Al)O ₁₀(OH) ₈	2/m	C2/m
Sudoite	Mg ₂(Al,Fe) ₃Si ₃AlO ₁₀(OH) ₈	2/m	C2/m

Formation

It has been first discovered in the Knollenberg Keuper formation, in the village of Plochingen, Stuttgart Region (Baden-Württemberg, Germany).^[4] Despite being an unlikely mineral, it has been described in every continent but Antarctica and Oceania. It is found mainly in hydrothermal or high-pressure/low-temperature (HP/LT) metamorphism contexts^[5]^[6]^[7]

Use

This mineral has been used as gemstone for the production of personal ornaments, beads and pendants, during the Early Ceramic Age (500 BC – 500 AD), in the Lesser Antilles.^[8] The precise source of such formation of sudoite allowing to carve artifacts in rather large blocks remain unknown.

References

^ Sudoite mineral information and data Mindat
^ Sudoite Mineral Data Webmineral
^ Kohyama, Norihiko (2000). "In memory of Prof. Toshio Sudo". Clay Science. 11 (2): 103–105. doi:10.11362/jcssjclayscience1960.11.103.
^ v. Engelhardt, W.; Müller, Germ; Kromer, H. (1962). "Dioktaedrischer Chlorit ("Sudoit") in Sedimenten des Mittleren Keupers von Plochingen (Württ.)". Naturwissenschaften. 49 (9): 205–206. Bibcode:1962NW.....49..205V. doi:10.1007/BF00633957. ISSN 1432-1904. S2CID 21590699.
^ Fransolet, André-Mathieu; Bourguignon, P. (1978). "Di/trioctahedral chlorite in quartz veins from the Ardenne, Belgium". The Canadian Mineralogist. 16 (3): 365–373.
^ Goffé, Bruno; Michard, André; Kienast, Jean Robert; Le Mer, Olivier (1988). "A case of obduction-related high-pressure, low-temperature metamorphism in upper crustal nappes, Arabian continental margin, Oman: P-T paths and kinematic interpretation". Tectonophysics. The Ophiolites of Man. 151 (1): 363–386. Bibcode:1988Tectp.151..363G. doi:10.1016/0040-1951(88)90253-3. ISSN 0040-1951.
^ Ruiz Cruz, María Dolores; de Galdeano, Carlos Sanz (2005). "Compositional and structural variation of sudoite from the Betic Cordillera (Spain): a TEM/AEM study". Clays and Clay Minerals. 53 (6): 639–652. Bibcode:2005CCM....53..639C. doi:10.1346/CCMN.2005.0530610. hdl:10261/18786. S2CID 52107572. Retrieved 2018-10-20.
^ Queffelec, Alain; Bellot-Gurlet, Ludovic; Foy, Eddy; Lefrais, Yannick; Fritsch, Emmanuel (2021). "First identification of sudoite in the Caribbean Ceramic Age lapidary craftsmanship". Gems and Gemology. 57 (3): 206–226. doi:10.5741/GEMS.57.3.206. S2CID 245282849.

attribution translated from fr:Sudoïte

[1] Sudoite mineral information and data Mindat

[2] Sudoite Mineral Data Webmineral

[3] Kohyama, Norihiko (2000). "In memory of Prof. Toshio Sudo". Clay Science. 11 (2): 103–105. doi:10.11362/jcssjclayscience1960.11.103.

[4] v. Engelhardt, W.; Müller, Germ; Kromer, H. (1962). "Dioktaedrischer Chlorit ("Sudoit") in Sedimenten des Mittleren Keupers von Plochingen (Württ.)". Naturwissenschaften. 49 (9): 205–206. Bibcode:1962NW.....49..205V. doi:10.1007/BF00633957. ISSN 1432-1904. S2CID 21590699.

[5] Fransolet, André-Mathieu; Bourguignon, P. (1978). "Di/trioctahedral chlorite in quartz veins from the Ardenne, Belgium". The Canadian Mineralogist. 16 (3): 365–373.

[6] Goffé, Bruno; Michard, André; Kienast, Jean Robert; Le Mer, Olivier (1988). "A case of obduction-related high-pressure, low-temperature metamorphism in upper crustal nappes, Arabian continental margin, Oman: P-T paths and kinematic interpretation". Tectonophysics. The Ophiolites of Man. 151 (1): 363–386. Bibcode:1988Tectp.151..363G. doi:10.1016/0040-1951(88)90253-3. ISSN 0040-1951.

[7] Ruiz Cruz, María Dolores; de Galdeano, Carlos Sanz (2005). "Compositional and structural variation of sudoite from the Betic Cordillera (Spain): a TEM/AEM study". Clays and Clay Minerals. 53 (6): 639–652. Bibcode:2005CCM....53..639C. doi:10.1346/CCMN.2005.0530610. hdl:10261/18786. S2CID 52107572. Retrieved 2018-10-20.

[8] Queffelec, Alain; Bellot-Gurlet, Ludovic; Foy, Eddy; Lefrais, Yannick; Fritsch, Emmanuel (2021). "First identification of sudoite in the Caribbean Ceramic Age lapidary craftsmanship". Gems and Gemology. 57 (3): 206–226. doi:10.5741/GEMS.57.3.206. S2CID 245282849.

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Sudoite

Characteristics

Classification

Formation

Use

References

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