USA HISTORY

Detailed explanation-1: -(A porphyry is an igneous rock containing conspicuous crystals, called phenocrysts, surrounded by a matrix of finer-grained minerals or glass or both.) In most rocks, both alkali and plagioclase feldspar s occur as irregularly shaped grains with only a few or no crystal faces.

Detailed explanation-2: -Porphyritic is an adjective used in geology to describe igneous rocks with a distinct difference in the size of mineral crystals, with the larger crystals known as phenocrysts. Both extrusive and intrusive rocks can be porphyritic, meaning all types of igneous rocks can display some degree of porphyritic texture.

Detailed explanation-3: -Porphyritic rock is igneous rock which is characterized by large crystals surrounded by a background of material with very small crystals. The scenario for the production of such rocks involves the formation of certain types of mineral crystals over a long period deep in the earth.

Detailed explanation-4: -Answer and Explanation: Porphyritic texture is an igneous rock textures that is characterized by two distinct mineral sizes. When looking at this type of igneous rock, large crystals can be seen within a matrix of finer grained rocks.

Detailed explanation-5: -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.