Comenditic rhyolite
A rock classification type
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A variety of peralkaline rhyolite of TAS field R in which Al2O3 > 1.33 x total iron as FeO + 4.4.
A sodic rhyolite containing alkalic amphibole and/or pyroxene.
A sodic rhyolite containing alkalic amphibole and/or pyroxene.
Unique Identifiers
Mindat ID:
48454
Long-form identifier:
mindat:1:1:48454:5
Classification of Comenditic rhyolite

Rhyolite appears in field 3 in the QAPF diagram.

Rhyolite is found in field 'R' in the TAS diagram.
Mineralogy of Comenditic rhyolite
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. |
| Silica > Quartz | SiO2 |
Non-essential minerals - these minerals are common, sometimes major components, but are not always present:
| Alkali pyroxene | A petrological name for the sodium-rich pyroxenes aegirine and aegirine-augite. |
| Amphibole | (Na, K, ◻)(Ca,Na)2(Mg,Fe,Al)5((Si,Al)8O22)(OH,F,Cl,O)2 |
| Feldspar > Plagioclase | (Na,Ca)[(Si,Al)AlSi2]O8 |
Age distribution
Recorded ages:
Phanerozoic : 137.2 ± 0.8 Ma to 0.11 ± 0.10 Ma - based on 6 recorded ages.
Synonyms of Comenditic rhyolite
Common Associates
Associated Minerals Based on Photo Data:
| 1 photo of Comenditic rhyolite associated with Montdorite | (K,Na)2(Fe2+,Mn2+,Mg)5(Si4O10)2(OH,F)4 |
Internet Links for Comenditic rhyolite
mindat.org URL:
https://www.mindat.org/min-48454.html
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