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Iolite
A variety of Cordierite
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About Iolite
Formula:
(Mg,Fe)2Al3(AlSi5O18)
Colour:
blue to blue–violet color
Name for gem-grade, violet-blue cordierite.
Visit gemdat.org for gemological information about Iolite.
Visit gemdat.org for gemological information about Iolite.Unique Identifiers
Mindat ID:
5119 (as Iolite)
1128 (as Cordierite)
1128 (as Cordierite)
Long-form identifier:
mindat:1:1:5119:0 (as Iolite)
mindat:1:1:1128:6 (as Cordierite)
mindat:1:1:1128:6 (as Cordierite)
Similar Names
| Eolite | A synonym of Realgar | |
| Eulite | A synonym of Ferrosilite | |
| Iglite | A synonym of Aragonite | |
| Ihlëite | A synonym of Copiapite | |
| Ijolite | A rock classification type | |
| Illite | A variety of Muscovite | K0.65Al2.0[Al0.65Si3.35O10](OH)2 |
| Iodite | A synonym of Iodargyrite | |
| Iozite | A synonym of Wüstite | |
| Ixolite | ||
| Jolite | A synonym of Cordierite | |
| Oolite | A rock subtype |
Physical Properties of Iolite
Colour:
blue to blue–violet color
Comment:
Cause of the color can be attributed to the charge transfer between Fe2+ on the octahedron and Fe3+ in the edge-shared T11 tetrahedra in the iolite.
(1)The color coordinates a* and b* were the main factors affecting the variation of the chroma C*.
(2)Fe is mainly present as Fe2+ and controls the lightness L* and the hue angle h°, while Mn does not have a significant effect on the color of iolite.
(3)The intervalence charge transfer between Fe2+ and Fe3+ is responsible for the blue color of iolite.
(4)The color parameters of iolite are affected by the change of light sources, and the hue angle h° is the most affected.
(1)The color coordinates a* and b* were the main factors affecting the variation of the chroma C*.
(2)Fe is mainly present as Fe2+ and controls the lightness L* and the hue angle h°, while Mn does not have a significant effect on the color of iolite.
(3)The intervalence charge transfer between Fe2+ and Fe3+ is responsible for the blue color of iolite.
(4)The color parameters of iolite are affected by the change of light sources, and the hue angle h° is the most affected.
Chemistry of Iolite
Mindat Formula:
(Mg,Fe)2Al3(AlSi5O18)
Element Weights:
Common Associates
Associations Based on Photo Data:
| 4 photos of Iolite associated with Cordierite | Mg2Al4Si5O18 |
| 3 photos of Iolite associated with Pyrrhotite | Fe1-xS |
| 2 photos of Iolite associated with Almandine | Fe2+3Al2(SiO4)3 |
| 2 photos of Iolite associated with Biotite | K(Fe2+/Mg)2(Al/Fe3+/Mg/Ti)([Si/Al/Fe]2Si2O10)(OH/F)2 |
| 1 photo of Iolite associated with Sillimanite | Al2(SiO4)O |
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 Iolite
mindat.org URL:
https://www.mindat.org/min-5119.html
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Please feel free to link to this page.
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References for Iolite
Localities for Iolite
Showing 25 localities.
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.
Argentina | |
| Herrmann et al. (2007) |
Australia | |
| Thompson (ed.) |
| Thompson (ed) | |
| Cave et al. (2022) |
Austria | |
| Erwin Löffler collection |
Brazil | |
| Karel Bal Collection |
| Sauer (1982) | |
| Sauer (1982) |
Canada | |
| - (n.d.) |
China | |
| Liu (2016, April) |
Greenland | |
| Bøggild (1953) |
| Bøggild (1953) |
India | |
| www.d4uweb.com (2010) |
Myanmar | |
| Themelis (2008) |
| Themelis (2008) |
| Themelis (2008) |
| Themelis (2008) | |
Norway | |
| Mason (1976) |
Russia | |
| Zaitsev et al. (2022) |
| Mikhailova et al. (2018) |
Sri Lanka | |
| Dissanayake et al. (2000) |
| Dissanayake et al. (2000) |
USA | |
| Philpotts et al. (1998) |
| The Geology of New Hampshire (1878) |
Gneiss quarry, Ebersdorf, Klein-Pöchlarn, Melk District, Lower Austria, Austria