Phyric
A phenocryst is an early forming, relatively large and usually conspicuous crystal distinctly larger than the grains of the rock groundmass of an igneous rock. Such rocks that have a distinct difference in the size of the crystals are called porphyries, and the adjective porphyritic is used to describe them. Phenocrysts often have euhedral forms, either due to early growth within a magma, or by post-emplacement recrystallization. Normally the term phenocryst is not used unless the crystals are directly observable, which is sometimes stated as greater than 0.5 mm (0.020 in) in diameter. Phenocrysts below this level, but still larger than the groundmass crystals, are termed microphenocrysts. Very large phenocrysts are termed megaphenocrysts. Some rocks contain both microphenocrysts and megaphenocrysts. In metamorphic rocks, crystals similar to phenocrysts are called porphyroblasts.
Phenocrysts are more often found in the lighter (higher silica) igneous rocks such as felsites and andesites, although they occur throughout the igneous spectrum including in the ultramafics. The largest crystals found in some pegmatites are often phenocrysts being significantly larger than the other minerals.
S.E.N.N.A
- 2022-12-21T00:00:00.000000Z
Back N Forth
- 2022-10-19T00:00:00.000000Z
Feel Alive
- 2022-08-19T00:00:00.000000Z
Atlantis
- 2022-04-08T00:00:00.000000Z
Live Fast
- 2022-02-15T00:00:00.000000Z
Barricades
- 2021-12-14T00:00:00.000000Z
One Family
- 2021-10-22T00:00:00.000000Z
Imagination
- 2021-05-27T00:00:00.000000Z
For You
- 2021-04-08T00:00:00.000000Z
Hold On To Me
- 2021-03-29T00:00:00.000000Z
Warning
- 2021-02-04T00:00:00.000000Z
50.000 Miles
- 2021-01-12T00:00:00.000000Z
Supernova
- 2020-11-03T00:00:00.000000Z
Afterlife
- 2020-09-24T00:00:00.000000Z
In Blood
- 2020-08-25T00:00:00.000000Z
Close To Me
- 2020-08-06T00:00:00.000000Z
Love
- 2020-07-09T00:00:00.000000Z
Falling
- 2019-11-29T00:00:00.000000Z
Similar Artists