Porphyry
A rock subtype
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About Porphyry
Not a root name, but a texturally-based name for any rock with coarse phenocrysts in a finer groundmass. Most commonly used for felsic rocks such as rhyolites, granites, etc.
An igneous rock of any composition that contains conspicuous phenocrysts in a fine-grained groundmass; a porphyritic igneous rock. The term (from the Ancient Greek word πορφύρα (porphyra) for the colour purple and a purple dye) was first applied to a purple-red rock quarried in Egypt and characterized by phenocrysts of alkali feldspar. The rock name descriptive of the groundmass composition usually precedes the term; e.g., diorite porphyry. In many cases the main phenocryst minerals precedes the name, e.g. quartz porphyry or quartz-feldspar porphyry.
Porphyrite is a mostly obsolete variety with dominant plagioclase phenocrysts.
An igneous rock of any composition that contains conspicuous phenocrysts in a fine-grained groundmass; a porphyritic igneous rock. The term (from the Ancient Greek word πορφύρα (porphyra) for the colour purple and a purple dye) was first applied to a purple-red rock quarried in Egypt and characterized by phenocrysts of alkali feldspar. The rock name descriptive of the groundmass composition usually precedes the term; e.g., diorite porphyry. In many cases the main phenocryst minerals precedes the name, e.g. quartz porphyry or quartz-feldspar porphyry.
Porphyrite is a mostly obsolete variety with dominant plagioclase phenocrysts.
Unique Identifiers
Mindat ID:
48434
Long-form identifier:
mindat:1:1:48434:1
GUID
(UUID V4):
(UUID V4):
461f7602-7750-4ee8-843c-c5108c3ca30e
Classification of Porphyry
Sub-divisions of Porphyry
- Porphyry
- Amygdalophyre
- Basite-porphyry
- Bornite (of Pinkerton)
- Chlorophyre
- Cristulite
- Cumulophyre
- Felseid
- Felsogranophyre
- Haüynophyre
- Leucitophyre
- Nepheline porphyry
- Ouachitite
- Porphyrite
- Porphyritic olivine-gabbro
- Porphyritic phonolite
- Porphyritic trachyte
- Spurine
- Uralite porphyry
- Biotite-feldspar porphyry
- Feldspar porphyry
- Hornblende porphyry
- Augite porphyry
- Quartz porphyry
- Quartz-feldspar porphyry
- Quartz-feldspar-biotite porphyry
- Vitrophyric porphyry
- Nepheline-feldspar porphyry
- Alsbachite
- Imperial Porphyry
Mineralogy of Porphyry
Non-essential minerals - these minerals are common, sometimes major components, but are not always present:
Feldspar | A petrological term for Feldspar Group. |
Mica | A petrological term for Mica Group. |
Mica > Biotite | K(Fe2+/Mg)2(Al/Fe3+/Mg/Ti)([Si/Al/Fe]2Si2O10)(OH/F)2 |
Silica > Quartz | SiO2 |
Age distribution
Recorded ages:
Phanerozoic : 290 Ma to 135 ± 3 Ma - based on 5 recorded ages.
Synonyms of Porphyry
Other Language Names for Porphyry
Varieties of Porphyry
Imperial Porphyry | Trade name for a famous ancient dimension stone from the Eastern Desert of Egypt. |
Common Associates
Associated Minerals Based on Photo Data:
1 photo of Porphyry associated with Clinozoisite | (CaCa)(AlAlAl)O[Si2O7][SiO4](OH) |
1 photo of Porphyry associated with Manganese Dendrites | |
1 photo of Porphyry associated with Hornblende Root Name Group | ◻Ca2(Z2+4Z3+)(AlSi7O22)(OH,F,Cl)2 |
1 photo of Porphyry associated with Quartz | SiO2 |
1 photo of Porphyry associated with Albite | Na(AlSi3O8) |
1 photo of Porphyry associated with Microdiorite | |
1 photo of Porphyry associated with Chlorite Group |
Internet Links for Porphyry
mindat.org URL:
https://www.mindat.org/min-48434.html
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References for Porphyry
Reference List:
Odra alluvial deposits, Opole Voivodeship, Poland