Foid-syenitoid
A rock classification type
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About Foid-syenitoid
A coarse-grained crystalline rock with <90% mafics, 10-60% of felsics being foids and alkali feldspar > plagioclase.
Unique Identifiers
Mindat ID:
50553
Long-form identifier:
mindat:1:1:50553:8
Classification of Foid-syenitoid
Foid-syenitic-rocks are in sections 11 and 12 of the QAPF diagram.
Sub-divisions of Foid-syenitoid
Mineralogy of Foid-syenitoid
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 |
| Mica > Biotite | K(Fe2+/Mg)2(Al/Fe3+/Mg/Ti)([Si/Al/Fe]2Si2O10)(OH/F)2 |
Synonyms of Foid-syenitoid
Internet Links for Foid-syenitoid
mindat.org URL:
https://www.mindat.org/min-50553.html
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References for Foid-syenitoid
Reference List:
Ilímaussaq complex, Kujalleq, Greenland