PHENOCRYSTS (EN: phenocrysts, impregnations, insets; DE: Einsprenglinge, Einlagerungen; FR: phenocristaux, minerais disséminés; ES: fenocristales, diseminaciones, impregnaciones; RU: вкрапленники) are the relatively large crystals of the minerals, which are prominent within the mass of the magmatic rocks because of their size and shape. There are the synonyms for the phenocrysts the phenocrystals, porphyric isolates, and megacrysts (the very large phenocrysts). The phenocrysts are characteristic for the porphyric or porphyritic rocks, the phenocrysts are formed from the same magma, from which there has formed the rock itself, but under other physical-chemical conditions in comparison with the minerals of the major mass.