Andesite rock. Polarised light micrograph of andesite, a volcanic rock with a typical porphyritic texture. Large twinned crystals (phenocrysts) of fel

---

Andesite rock. Polarised light micrograph of andesite, a volcanic rock with a typical porphyritic texture. Large twinned crystals (phenocrysts) of feldspar (white) float in a finely crystalline matrix (black). The porphyritic texture is caused by ex-solution, a process of separation that takes place during successive phases of crystallisation in the lava. This thin section image has been obtained using cross-polarised light (or 'crossed nichols').

---

Size: 4950px × 3680px
Photo credit: © DIRK WIERSMA/SCIENCE PHOTO LIBRARY / Alamy / Afripics
License: Licensed
Model Released: No

Keywords: -solution, andesite, cross, cross-polarised, cross-polarized, crossed, crystal, crystalline, crystals, earth, feldspar, geological, geology, light, lm, micrograph, microscope, microscopy, mineral, mineralogy, minerals, nichols, phenocryst, phenocrysts, plm, polarised, polarized, porphyritic, rock, rocks, science, section, sectioned, separated, separation, thin, volcanic