Sugilite
A valid IMA mineral species
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About Sugilite
Ken-ichi Sugi
Formula:
KNa2Fe3+2Li3[Si12O30]
Colour:
Purple, violet, light brownish-yellow, colourless in transmitted light
Lustre:
Vitreous
Hardness:
5½ - 6½
Specific Gravity:
2.74 - 2.79
Crystal System:
Hexagonal
Member of:
Name:
Named by Nobuhide Murakami, Toshio Kato, Yasunori Miura, and Fumitoshi Hirowatari in 1976 in honor of Ken-ichi Sugi (杉健一) (15 May 1901, Kashiwazaki, Niigata Prefecture, Japan - 16 July 1948, Fukuoka, Fukuoka Prefecture, Japan), petrologist at the Imperial University Kyushu, who first found the occurrence of the mineral with M. Kutsuna.
Sugilite is an example of a mineral name pronounced wrongly more often than correctly. Named after Japanese petrologist Dr. Ken-ichi Sugi, whose name is pronounced with a hard "g" (as in "geese"), whereas most English speakers mispronounce it with a soft "g" (as in "gene"). This wasn't much of an issue when sugilite was just an obscure ugly greenish-yellowish-brown rock-forming mineral from Japan. When it was found in South Africa as large quantities of bright purple lapidary rock and thousands of people in the gem trade started talking about it, the bad pronunciation became entrenched (Alfredo Petrov, 2014).
Sugilite is an example of a mineral name pronounced wrongly more often than correctly. Named after Japanese petrologist Dr. Ken-ichi Sugi, whose name is pronounced with a hard "g" (as in "geese"), whereas most English speakers mispronounce it with a soft "g" (as in "gene"). This wasn't much of an issue when sugilite was just an obscure ugly greenish-yellowish-brown rock-forming mineral from Japan. When it was found in South Africa as large quantities of bright purple lapidary rock and thousands of people in the gem trade started talking about it, the bad pronunciation became entrenched (Alfredo Petrov, 2014).
Type Locality:
Visit gemdat.org for Unique Identifiers
Mindat ID:
3822
Long-form identifier:
mindat:1:1:3822:1
IMA Classification of Sugilite
Approved
IMA Formula:
KNa2Fe3+2(Li3Si12)O30
Approval year:
1974
First published:
1976
Classification of Sugilite
9.CM.05
9 : SILICATES (Germanates)
C : Cyclosilicates
M : [Si6O18]12- 6-membered double rings (sechser-Doppelringe)
9 : SILICATES (Germanates)
C : Cyclosilicates
M : [Si6O18]12- 6-membered double rings (sechser-Doppelringe)
63.2.1a.9
63 : CYCLOSILICATES Condensed Rings
2 : Condensed Rings (Milarite - Osumilite group)
63 : CYCLOSILICATES Condensed Rings
2 : Condensed Rings (Milarite - Osumilite group)
16.1.17
16 : Silicates Containing Aluminum and other Metals
1 : Aluminosilicates of Li
16 : Silicates Containing Aluminum and other Metals
1 : Aluminosilicates of Li
Mineral Symbols
As of 2021 there are now IMA–CNMNC approved mineral symbols (abbreviations) for each mineral species, useful for tables and diagrams.
Please only use the official IMA–CNMNC symbol. Older variants are listed for historical use only.
Please only use the official IMA–CNMNC symbol. Older variants are listed for historical use only.
| Symbol | Source | Reference |
|---|---|---|
| Sug | IMA–CNMNC | Warr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43 |
| Sug | The Canadian Mineralogist (2019) | The Canadian Mineralogist (2019) The Canadian Mineralogist list of symbols for rock- and ore-forming minerals (December 30, 2019). download |
Pronunciation of Sugilite
Pronunciation:
| Play | Recorded by | Country |
|---|---|---|
| Jolyon Ralph | United Kingdom |
Physical Properties of Sugilite
Vitreous
Transparency:
Transparent, Translucent
Colour:
Purple, violet, light brownish-yellow, colourless in transmitted light
Streak:
White
Hardness:
5½ - 6½ on Mohs scale
Cleavage:
Poor/Indistinct
{0001} poor
{0001} poor
Density:
2.74 - 2.79 g/cm3 (Measured) 2.80 g/cm3 (Calculated)
Optical Data of Sugilite
Type:
Uniaxial (-)
RI values:
nω = 1.595 - 1.611 nε = 1.590 - 1.607
Max. Birefringence:
δ = 0.004 - 0.005
Based on recorded range of RI values above.
Based on recorded range of RI values above.
Interference Colours:
The colours simulate birefringence patterns seen in thin section under crossed polars. They do not take into account mineral colouration or opacity.
Michel-Levy Bar The default colours simulate the birefringence range for a 30 µm thin-section thickness. Adjust the slider to simulate a different thickness.
Grain Simulation You can rotate the grain simulation to show how this range might look as you rotated a sample under crossed polars.
The colours simulate birefringence patterns seen in thin section under crossed polars. They do not take into account mineral colouration or opacity.
Michel-Levy Bar The default colours simulate the birefringence range for a 30 µm thin-section thickness. Adjust the slider to simulate a different thickness.
Grain Simulation You can rotate the grain simulation to show how this range might look as you rotated a sample under crossed polars.
Surface Relief:
Moderate
Pleochroism:
Weak
Chemistry of Sugilite
Mindat Formula:
KNa2Fe3+2Li3[Si12O30]
Element Weights:
Common Impurities:
Ti,H2O
Crystallography of Sugilite
Crystal System:
Hexagonal
Class (H-M):
6/mmm (6/m 2/m 2/m) - Dihexagonal Dipyramidal
Space Group:
P6/mcc
Setting:
P6/mcc
Cell Parameters:
a = 10.007 Å, c = 14.000 Å
Ratio:
a:c = 1 : 1.399
Unit Cell V:
1,214.13 ų (Calculated from Unit Cell)
Z:
2
Crystal Structure
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Data courtesy of the American Mineralogist Crystal Structure Database. Click on an AMCSD ID to view structure
| ID | Species | Reference | Link | Year | Locality | Pressure (GPa) | Temp (K) |
|---|---|---|---|---|---|---|---|
| 0001157 | Sugilite | Armbruster T, Oberhansli R (1988) Crystal chemistry of double-ring silicates: Structures of sugilite and brannockite American Mineralogist 73 595-600 |  | 1988 | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 8.65 Å | (7) |
| 6.98 Å | (13) |
| 4.78 Å | (7b) |
| 4.32 Å | (100) |
| 4.06 Å | (55) |
| 3.68 Å | (13) |
| 3.50 Å | (25) |
| 3.27 Å | (7) |
| 3.25 Å | (8) |
| 3.19 Å | (80) |
| 2.876 Å | (50b) |
| 2.725 Å | (13) |
| 2.678 Å | (11b) |
| 2.499 Å | (18) |
| 2.401 Å | (7b) |
| 2.273 Å | (6b) |
| 2.231 Å | (8b) |
| 2.159 Å | (13) |
| 1.983 Å | (13b) |
| 1.890 Å | (8) |
| 1.874 Å | (11) |
| 1.827 Å | (8b) |
| 1.820 Å | (7b) |
| 1.757 Å | (7b) |
| 1.711 Å | (8b) |
| 1.666 Å | (10b) |
| 1.627 Å | (6b) |
| 1.551 Å | (7b) |
| 1.508 Å | (8b) |
| 1.439 Å | (7) |
| 1.420 Å | (5b) |
| 1.391 Å | (10) |
| 1.385 Å | (5) |
| 1.364 Å | (5) |
| 1.311 Å | (5) |
| 1.200 Å | (5) |
Reference:
Comments:
JCPDS 29-824
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 4a: Earth’s earliest continental crust | >4.4-3.0 |
| 19 : Granitic intrusive rocks | |
| High-? alteration and/or metamorphism | |
| 32 : Ba/Mn/Pb/Zn deposits, including metamorphic deposits | |
| Stage 4b: Highly evolved igneous rocks | >3.0 |
| 35 : Ultra-alkali and agpaitic igneous rocks |
Type Occurrence of Sugilite
General Appearance of Type Material:
Subhedral grain forming (3-8 %) or the rock.
Place of Conservation of Type Material:
Yamaguchi University, Yamaguchi, Japan.
Sakurai Museum, Tokyo, Japan.
National Science Museum, Tokyo, Japan.
The Natural History Museum, London, England, 1975,342.
National Museum of Natural History, Washington, D.C., USA, 133982.
Sakurai Museum, Tokyo, Japan.
National Science Museum, Tokyo, Japan.
The Natural History Museum, London, England, 1975,342.
National Museum of Natural History, Washington, D.C., USA, 133982.
Geological Setting of Type Material:
Aegirine syenite.
Associated Minerals at Type Locality:
Synonyms of Sugilite
Other Language Names for Sugilite
Relationship of Sugilite to other Species
Member of:
Other Members of Osumilite Group:
| Agakhanovite-(Y) | K◻2(YCa)Be3[Si12O30] | Hex. 6/mmm (6/m 2/m 2/m) : P6/mcc |
| Almarudite | K◻2Mn2+2(Be2Al)[Si12O30] | Hex. 6/mmm (6/m 2/m 2/m) : P6/mmm |
| Aluminosugilite | KNa2Al2Li3[Si12O30] | Hex. 6/mmm (6/m 2/m 2/m) : P6/mcc |
| Armenite | Ba(H2O)2Ca2Al3[Al3Si9O30] | Orth. mmm (2/m 2/m 2/m) : Pnna |
| Berezanskite | K◻2Ti2Li3[Si12O30] | Hex. 6/mmm (6/m 2/m 2/m) : P6/mcc |
| Brannockite | K◻2Sn2Li3[Si12O30] | Hex. 6/mmm (6/m 2/m 2/m) : P6/mcc |
| Chayesite | K◻2Mg2(Mg2Fe3+)[Si12O30] | Hex. 6/mmm (6/m 2/m 2/m) : P6/mcc |
| Darapiosite | KNa2Mn2(Zn2Li)[Si12O30] | Hex. 6/mmm (6/m 2/m 2/m) : P6/mcc |
| Dusmatovite | K(K◻)Mn2+2Zn3[Si12O30] | Hex. 6/mmm (6/m 2/m 2/m) : P6/mcc |
| Eifelite | KNa2(MgNa)Mg3[Si12O30] | Hex. 6/mmm (6/m 2/m 2/m) : P6/mcc |
| Friedrichbeckeite | K(◻Na)Mg2(Be2Mg)[Si12O30] | Hex. 6/mmm (6/m 2/m 2/m) : P6/mcc |
| Klöchite | K◻2(Fe2+Fe3+)Zn3[Si12O30] | Hex. 6/mmm (6/m 2/m 2/m) : P63/mmc |
| Laurentthomasite | K◻2Mg2(Be2Al)[Si12O30] | Hex. 6/mmm (6/m 2/m 2/m) : P6/mcc |
| Merrihueite | K(◻Na)Fe2+2Fe2+3[Si12O30] | Hex. 6/mmm (6/m 2/m 2/m) : P6/mcc |
| Milarite | K(◻H2O)Ca2(Be2Al)[Si12O30] | Hex. 6/mmm (6/m 2/m 2/m) : P6/mcc |
| Oftedalite | K◻2(ScCa)Be3[Si12O30] | Hex. 6/mmm (6/m 2/m 2/m) : P6/mcc |
| Osumilite | K◻2Fe2+2Al3[Al2Si10O30] | Hex. 6/mmm (6/m 2/m 2/m) : P6/mcc |
| Osumilite-(Mg) | K◻2Mg2Al3[Al2Si10O30] | Hex. 6/mmm (6/m 2/m 2/m) : P6/mcc |
| Poudretteite | K◻2Na2B3[Si12O30] | Hex. 6/mmm (6/m 2/m 2/m) : P6/mcc |
| Roedderite | K(◻Na)Mg2Mg3[Si12O30] | Hex. 6 m2 : P62c |
| Shibkovite | K(◻K)Ca2Zn3[Si12O30] | Hex. 6/mmm (6/m 2/m 2/m) : P6/mcc |
| Sogdianite | K◻2Zr2Li3[Si12O30] | Hex. 6/mmm (6/m 2/m 2/m) : P6/mcc |
| Trattnerite | ◻(◻)2Fe3+2Mg3[Si12O30] | Hex. 6/mmm (6/m 2/m 2/m) : P6/mcc |
| UM1990-73-SiO:KMnNaZn | K(KNa0.5◻0.5)(Mn1.5Na0.5)Zn3[Si12O30] | Hex. |
| Unnamed (Mn3+-dominant analog of Sugilite) | KNa2Mn3+2Li3[Si12O30] | |
| Yagiite | Na◻2Mg2Al3[Al2Si10O30] | Hex. 6/mmm (6/m 2/m 2/m) : P6/mcc |
Common Associates
Associated Minerals Based on Photo Data:
| 38 photos of Sugilite associated with Pectolite | NaCa2Si3O8(OH) |
| 19 photos of Sugilite associated with Effenbergerite | BaCuSi4O10 |
| 19 photos of Sugilite associated with Wesselsite | SrCuSi4O10 |
| 17 photos of Sugilite associated with Quartz | SiO2 |
| 11 photos of Sugilite associated with Albite | Na(AlSi3O8) |
| 10 photos of Sugilite associated with Hennomartinite | SrMn3+2(Si2O7)(OH)2 · H2O |
| 8 photos of Sugilite associated with Strontioruizite | Sr2Mn3+2Si4O11(OH)4 · 2H2O |
| 7 photos of Sugilite associated with Aegirine | NaFe3+Si2O6 |
| 7 photos of Sugilite associated with Richterite | Na(NaCa)Mg5(Si8O22)(OH)2 |
| 6 photos of Sugilite associated with Katayamalite | KLi3Ca7Ti2(SiO3)12(OH)2 |
Related Minerals - Strunz-mindat Grouping
| 9.CM. | Agakhanovite-(Y) | K◻2(YCa)Be3[Si12O30] |
| 9.CM.05 | Friedrichbeckeite | K(◻Na)Mg2(Be2Mg)[Si12O30] |
| 9.CM.05 | Laurentthomasite | K◻2Mg2(Be2Al)[Si12O30] |
| 9.CM.05 | UM1990-73-SiO:KMnNaZn | K(KNa0.5◻0.5)(Mn1.5Na0.5)Zn3[Si12O30] |
| 9.CM.05 | Eifelite | KNa2(MgNa)Mg3[Si12O30] |
| 9.CM.05 | Almarudite | K◻2Mn2+2(Be2Al)[Si12O30] |
| 9.CM.05 | Armenite | Ba(H2O)2Ca2Al3[Al3Si9O30] |
| 9.CM.05 | Merrihueite | K(◻Na)Fe2+2Fe2+3[Si12O30] |
| 9.CM.05 | Oftedalite | K◻2(ScCa)Be3[Si12O30] |
| 9.CM.05 | Roedderite | K(◻Na)Mg2Mg3[Si12O30] |
| 9.CM.05 | Shibkovite | K(◻K)Ca2Zn3[Si12O30] |
| 9.CM.05 | Sogdianite | K◻2Zr2Li3[Si12O30] |
| 9.CM.05 | Milarite | K(◻H2O)Ca2(Be2Al)[Si12O30] |
| 9.CM.05 | Berezanskite | K◻2Ti2Li3[Si12O30] |
| 9.CM.05 | Poudretteite | K◻2Na2B3[Si12O30] |
| 9.CM.05 | Darapiosite | KNa2Mn2(Zn2Li)[Si12O30] |
| 9.CM.05 | Chayesite | K◻2Mg2(Mg2Fe3+)[Si12O30] |
| 9.CM.05 | Osumilite-(Mg) | K◻2Mg2Al3[Al2Si10O30] |
| 9.CM.05 | Osumilite | K◻2Fe2+2Al3[Al2Si10O30] |
| 9.CM.05 | Trattnerite | ◻(◻)2Fe3+2Mg3[Si12O30] |
| 9.CM.05 | Brannockite | K◻2Sn2Li3[Si12O30] |
| 9.CM.05 | Klöchite | K◻2(Fe2+Fe3+)Zn3[Si12O30] |
| 9.CM.05 | Dusmatovite | K(K◻)Mn2+2Zn3[Si12O30] |
| 9.CM.05 | Yagiite | Na◻2Mg2Al3[Al2Si10O30] |
| 9.CM.9.CM. | Aluminosugilite | KNa2Al2Li3[Si12O30] |
| 9.CM.10 | Faizievite | K2Na(Ca6Na)Ti4Li6[Si6O18]2[Si12O30]F2 |
Radioactivity
Radioactivity:
| Element | % Content | Activity (Bq/kg) | Radiation Type |
|---|---|---|---|
| Uranium (U) | 0.0000% | 0 | α, β, γ |
| Thorium (Th) | 0.0000% | 0 | α, β, γ |
| Potassium (K) | 3.7791% | 1,172 | β, γ |
For comparison:
- Banana: ~15 Bq per fruit
- Granite: 1,000–3,000 Bq/kg
- EU exemption limit: 10,000 Bq/kg
Note: Risk is shown relative to daily recommended maximum exposure to non-background radiation of 1000 µSv/year. Note that natural background radiation averages around 2400 µSv/year so in reality these risks are probably extremely overstated! With infrequent handling and safe storage natural radioactive minerals do not usually pose much risk.
Interactive Simulator:
Note: The mass selector refers to the mass of radioactive mineral present, not the full specimen, also be aware that the matrix may also be radioactive, possibly more radioactive than this mineral!
Activity: –
| Distance | Dose rate | Risk |
|---|---|---|
| 1 cm | ||
| 10 cm | ||
| 1 m |
The external dose rate (D) from a radioactive mineral is estimated by summing the gamma radiation contributions from its Uranium, Thorium, and Potassium content, disregarding daughter-product which may have a significant effect in some cases (eg 'pitchblende'). This involves multiplying the activity (A, in Bq) of each element by its specific gamma ray constant (Γ), which accounts for its unique gamma emissions. The total unshielded dose at 1 cm is then scaled by the square of the distance (r, in cm) and multiplied by a shielding factor (μshield). This calculation provides a 'worst-case' or 'maximum risk' estimate because it assumes the sample is a point source and entirely neglects any self-shielding where radiation is absorbed within the mineral itself, meaning actual doses will typically be lower. The resulting dose rate (D) is expressed in microsieverts per hour (μSv/h).
D = ((AU × ΓU) + (ATh × ΓTh) + (AK × ΓK)) / r2 × μshield
Other Information
Health Risks:
No information on health risks for this material has been entered into the database. You should always treat mineral specimens with care.
Internet Links for Sugilite
mindat.org URL:
https://www.mindat.org/min-3822.html
Please feel free to link to this page.
Please feel free to link to this page.
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External Links:
References for Sugilite
Reference List:
Murakami, Nobuhide, Kato, Toshio, Miúra, Yasunori, Hirowatari, Fumitoshi (1976) Sugilite, a new silicate mineral from Iwagi Islet, Southwest Japan. Mineralogical Journal, 8 (2) 110-121 doi:10.2465/minerj.8.110
Kato, Toshio, Miúra, Yasunori, Murakami, Nobuhide (1976) Crystal structure of sugilite. Mineralogical Journal, 8 (3) 184-192 doi:10.2465/minerj.8.184
Fleischer, Michael, Cabri, Louis J., Nickel, Ernest H., Pabst, Adolf (1977) New Mineral Names. American Mineralogist, 62 (5-6) 593-600
Dunn, P. J., Brummer, J. J., Belsky, H. (1980) Sugilite, a second occurrence: Wessels mine, Kalahari manganese field, Republic of South Africa. The Canadian Mineralogist, 18 (1) 37-39
Shigley, James E., Koivula, John I., Fryer, C. W. (1987) The occurrence and gemological properties of Wessels Mine sugilite. Gems & Gemology, 23 (2) 78-89 doi:10.5741/gems.23.2.78
Armbruster, Thomas, Oberhänsli, Roland (1988) Crystal chemistry of double-ring silicates: Structures of sugilite and brannockite. American Mineralogist, 73 (5-6) 595-600
Kawachi, Y., Ashley, P. M., Vince, D., Goodwin, M. (1994) Sugilite in manganese silicate rocks from the Hoskins mine and Woods mine, New South Wales, Australia. Mineralogical Magazine, 58 (393) 671-677 doi:10.1180/minmag.1994.058.393.18
Geiger, C. A. (2009) A 57Fe Mössbauer spectroscopic study of sugilite, KNa2(Fe3+,Mn3+,Al)2Li3Si12O30. The Canadian Mineralogist, 47 (4) 927-931 doi:10.3749/canmin.47.3.927
Moore, John M., Kuhn, Barbara K., Mark, Darren F., Tsikos, Harilaos (2011) A sugilite-bearing assemblage from the Wolhaarkop breccia, Bruce iron-ore mine, South Africa: Evidence for alkali metasomatism and 40Ar-39Ar dating. European Journal of Mineralogy, 23 (4) 661-673 doi:10.1127/0935-1221/2011/0023-2117
Localities for Sugilite
symbol to view information about a locality.
The Locality List
- This locality has map coordinates listed.
- This locality has estimated coordinates.
ⓘ - Click for references and further information on this occurrence.
? - Indicates mineral may be doubtful at this locality.
- Good crystals or important locality for species.
- World class for species or very significant.
(TL) - Type Locality for a valid mineral species.
(FRL) - First Recorded Locality for everything else (eg varieties).
All localities listed without proper references should be considered as questionable.
Australia | |
| Kawachi et al. (1994) +1 other reference |
| Kawachi et al. (1994) |
Canada | |
| HORVÁTH et al. (2000) |
India | |
| Clark et al. (1980) | |
Italy | |
| Palenzona (1990) +1 other reference |
| Biagioni C. (Alpi Apuane, Lucca) |
Japan | |
| - (n.d.) |
| Mineralogical Journal Vol. 8 (1975) +5 other references |
| Imaoka et al. (2021) +1 other reference | |
South Africa | |
| Moore et al. (2011) +1 other reference |
| Pohl et al. (1991) |
| Cairncross et al. (1995) | |
| Williams et al. (2015) +2 other references | |
| Dunn et al. (1980) +5 other references | |
Tajikistan | |
| Pautov et al. (2004) +3 other references |
Quick NavTopAbout SugiliteUnique IdentifiersIMA Classification Classification Mineral SymbolsPronunciation Physical Properties Optical Data Chemistry Crystallography Crystal StructureX-Ray Powder DiffractionGeological EnvironmentType Occurrence SynonymsOther LanguagesRelationshipsCommon AssociatesStrunz-MindatRadioactivityOther InformationInternet Links References Localities Locality List
Iwagi Island, Ochi District, Ehime Prefecture, Japan