Porphyry

Classification：Igneous Rock

Porphyry is a general term for igneous porphyritic structure characterized by the structural characteristics of rock named.

Porphyry (porphyry) is igneous rocks, porphyritic structure has relatively strong, can be used as building material. Phenocrysts are usually composed of alkali feldspar or quartz, and the matrix is fine or cryptic crystal (vitreous body).
Porphyry is a general name for extrusive rocks, shallow igneous rocks and ultra shallow intrusive rocks which are phenocrysts of K-feldspar, feldspar or quartz. The word "Porphyry" comes from the Greek language porphyry, meaning purplish red. It originally refers to any igneous rock with phenocrysts. It was first used for a purple red rock with alkaline feldspar phenocryst. Some people think that is synonymous with porphyrite. Usually, the alkaline feldspar is phenocryst, and the matrix is fine or cryptocrystalline extrusive rock and Asacheng Iwa.

Porphyry is divided into two major categories: eruption rocks and shallow diagenetic rocks. The eruption rocks are formed by the eruption of volcanic magma. Because of the rapid cooling after the eruption, many fine grains are formed, and the shallow diagenetic rocks are formed by volcanic magma intruding into the shallow layer of the crust (generally 1.5-3 kilometer), and there are many nodal spots.

The eruption rocks are:
Rhyolite Porphyry
Rough porphyry
White granite porphyry

There are rocks:
Quartz porphyry
Granite porphyry
Normal Ban Yan

The word "Porphyry", by porphyrite evolved. Porphyrite by G. Agricola in 1546 first introduced the literature to describe the Egyptian lavender, with flecks of rock. After a long period of time, Porphyry and porphyrite respectively changed structure refers to the porphyritic trachyte andesitic rocks. Most of the rock scientists believe that most of Porphyry and porphyrite are neutral and acid rocks in chemical composition, so the common speckles are quartz, alkaline feldspar and plagioclase. The quartz usually develops six square BIMS and has a high temperature quartz shape; alkaline feldspar is usually permeable feldspar, ortho feldspar and feldspar with a hidden stripe structure or submicroscopic stripe structure. The plagioclase is usually medium feldspar, often subjected to magma erosion, or the formation of sodium plagioclase membrane, and can also form the polymerization of plagioclase by the flow of rock pulp. Speckles.
Habitually, the rock containing the alkaline feldspar and quartz speckles, or only one porphyry structure, is called Porphyry, such as the flower granite Porphyry; the porphyrite containing the long Shi Banjing and the porphyrite, such as the diorite porphyrite. For example, plagioclase and alkaline feldspar and / or quartz phenocrysts are also known as Porphyry, such as Hua Gang dioren Ban Yan. The porphyry rocks containing massive self form (sometimes semi self form) iron and magnesium minerals are usually intermediate, basic or ultrabasic veins, called "phylate porphyry". ALLGOVITE refers to Shi Banjing's basic rocks containing plagioclase. Albite porphyry and picrite porphyrite are sodium feldspar phenocrysts and olivine phenocrysts in porphyritic rocks. Whether it is Porphyry or porphyrite, are products of magmatic crystallization stage two. Therefore, their grain size is very different between the phenocrysts and the matrix. The phenocryst is formed by early stage magmatic crystallization and formed in the deeper part of the subsurface. The fine grain or cryptic matrix is a late stage magma crystallization product. The final emplacement depth, Porphyry and porphyrite are hypabyssal rocks, and often a dike, dikes, sills or small intrusive occurrence. Porphyry and porphyrite transition to deep formed rocks with the decrease of the number of speckles and the size of the granularity between the macula and the matrix, for example, the porphyritic granite is equivalent to the granite porphyry or the semi deep rock, and with the decrease in the number of speckles and the decrease of the matrix size (until the cryptic or vitreous) transition to the eruptive rock, such as the porphyritic rhyolite. Is the equivalent of hypabyssal extrusive rocks of rhyolite porphyry. Metal minerals related to Porphyry or porphyrite are often referred to as porphyry copper deposits, porphyry molybdenum ores, porphyry tungsten ores and Bin Yan iron ore, all of which are important deposits associated with the formation of shallow magmatism and post magmatic action. Some semi weathered rough or coarse porphyry porphyry is called medical stone -- medical stone because it contains many trace elements that human body needs and is dissolved.