A phenocryst is an early forming, relatively large and usually conspicuous crystal distinctly larger than the grains of the rock groundmass of an igneous...

partially resorbed phenocrysts or an accessory phase in basalts generated at depth. Phlogopite mica is a commonly known phenocryst and groundmass phase...

crystals (phenocrysts) that formed before the extrusion event that brought the magma to the surface, embedded in a finer-grained matrix. These phenocrysts are...

crystals (phenocrysts) of plagioclase formed prior to the extrusion that brought the magma to the surface, embedded in a finer-grained matrix. Phenocrysts of...

layers of materials. Porphyritic texture is one in which larger pieces (phenocrysts) are embedded in a background mass made of much finer grains. Fragmental...

common in American usage, while amygdale is more common in British usage. Phenocryst – Crystal larger than the rock grains that surround it in an igneous rock...

during eruption. Any larger crystals visible to the human eye, called phenocrysts, form earlier while slowly cooling in the magma reservoir. When igneous...

difference in size between the tiny matrix crystals and the much larger phenocrysts. Porphyries may be aphanites or phanerites, that is, the groundmass may...

glass in texture. They often contain clasts of other rocks and phenocrysts. Phenocrysts are crystals that are larger than the matrix and are identifiable...

peppering the lighter color minerals. Occasionally some individual crystals (phenocrysts) are larger than the groundmass, in which case the texture is known as...