Shonkinite
A rock classification type
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About Shonkinite
Name:
Its name, given by Weed and Pirsson in 1895, is derived from Shonkin, the Indian name for the Highwood Mountains of Montana.
First Recorded Locality:
A coarse-grained rock with abundant augite, some olivine, biotite or hornblende, and essential alkali feldspar and foids, usually nepheline. Now defined modally as a melanocratic variety of foid syenite in QAPF field 11. A dark-colored syenite composed chiefly of augite and alkali feldspar, and possibly containing olivine, hornblende, biotite, and nepheline.
Ref: AGI
Ref: AGI
Unique Identifiers
Mindat ID:
50577
Long-form identifier:
mindat:1:1:50577:8
Classification of Shonkinite
Foid-syenite is in section 11 of the QAPF diagram.
Sub-divisions of Shonkinite
- Shonkinite
Mineralogy of Shonkinite
Essential minerals - these are minerals that are required within the classification of this rock:
| Feldspar > Alkali Feldspar | A subgroup of the Feldspar Group, poor in calcium, and mostly rich in potassium. |
| Feldspathoid | A family of rock-forming minerals consisting of aluminosilicates of sodium, potassium, or calcium and having too ... |
Non-essential minerals - these minerals are common, sometimes major components, but are not always present:
| Amphibole > Hornblende | AnCa2(Z2+5-mZ3+m)(Si8-(n+m)Al(n+m))(OH,F,Cl)2 |
| Feldspathoid > Nepheline | Na3K(Al4Si4O16) |
| Mica > Biotite | K(Fe2+/Mg)2(Al/Fe3+/Mg/Ti)([Si/Al/Fe]2Si2O10)(OH/F)2 |
| Olivine | M2SiO4 |
First Recorded Occurrence of Shonkinite
Synonyms of Shonkinite
Common Associates
Associated Minerals Based on Photo Data:
| 5 photos of Shonkinite associated with Nepheline | Na3K(Al4Si4O16) |
| 5 photos of Shonkinite associated with Clinopyroxene Subgroup | |
| 5 photos of Shonkinite associated with K Feldspar | |
| 5 photos of Shonkinite associated with Biotite | K(Fe2+/Mg)2(Al/Fe3+/Mg/Ti)([Si/Al/Fe]2Si2O10)(OH/F)2 |
| 4 photos of Shonkinite associated with Magnetite | Fe2+Fe3+2O4 |
Internet Links for Shonkinite
mindat.org URL:
https://www.mindat.org/min-50577.html
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Michelsberg Quarry, Katzenbuckel, Eberbach, Rhein-Neckar-Kreis, Karlsruhe Region, Baden-Württemberg, Germany