Phonolite

Classification：Igneous Rock

An alkaline extrusive rock consists of fine-grained alkaline feldspar, nepheline, alkaline amphibole and alkaline pyroxene, and is distributed less on the earth.

Phonolite an alkaline eruption rock. The chemical composition of the equivalent of nepheline syenite. The content of alkali is high. The main minerals are alkaline feldspar, feldspar, alkaline pyroxene and alkaline hornblende. The alkaline feldspar is similar to feldspar or concealed striped feldspar, sodium feldspar and anaspore. Due to hitting along joints, it often gives out clear and loud noises.

It is often produced by small rock flow and rock clock. Phonolite is a rare rock. It accounts for about 0.1% of all extrusive rocks and is often present in small streams or filled in caldera. It is generally found in the alkaline rock distribution area. Shanxi Zijin Mountain, Jiangsu, Liaoning China Niangniangshan Gu and Tibet bamaoqiongzong distribution. The composition and nepheline syenite quite extrusive rock. Use the hammer to strike the rock, jingle, named. Light green or brownish gray, fat luster, dense. Often porphyritic texture and sometimes aphyric texture. The main minerals are alkaline feldspar, feldspar and alkaline dark minerals. Sometimes lepidomelane and chrysolite. Alkaline feldspar is mainly composed of feldspar, the second is anorthite, orthosite and albite, while plagioclase is rare. Feldspar in common with nepheline and leucite, analcime, Sodalite, nosean, Lan Fangshi etc.. Pyroxene is usually composed of sodium, common augite and albite, sometimes with diopside and titanaugite. Hornblende is also characterized by sodium rich, such as brown amphibole, reddish amphibole, sodium iron amphibole and sodium amphibole. Only in the form of speckles. Accessory minerals are magnetite, apatite, zircon, titanite, three oblique flash feldspar, melanite etc..

Classification:
According to the type of feldspar in rocks, Phonolite is divided into the following species.
The nepheline Phonolite, commonly known as Phonolite. Is mainly composed of alkali feldspar, nepheline and dark alkaline minerals. With the outline of the rules of crystal sanidine, alkaline nepheline, pyroxene phenocrysts often constitute. If there are more nepheline in the matrix, it often forms the six square and rectangular section of the self shape, which is called the Phonolite structure. If the matrix is mainly alkaline feldspar, and the crystal is near parallel, nepheline and alkaline dark minerals are filled between the feldspar microcrystals, which is called the rough surface structure.
The leucite Phonolite, gray white or dark grey rocks, porphyritic structure. Feldspar, garnet and a small amount of basic pyroxene often form phenocrysts but not calcite. Sometimes the white garnet is found only in the matrix. In white stone, inclusions of pyroxene, magnetite, apatite, and feldspar often have radial or concentric circles. The garnet is unstable. It is often replaced by feldspar and Jia Xiashi. It keeps the illusion of Phonolite. It is called Phonolite. According to the feldspathoid species also can be divided into sodalite Phonolite, zeolite Phonolite, hauyne Phonolite and nosean Phonolite.

Features：
Basically, volcanic rocks consist of alkaline feldspar and any other feldspar. The rocks are characterized by the presence of accessory feldspar and alkaline iron and magnesium minerals, with porphyritic structure and phenocrysts as alkaline feldspar, various kinds of accessory feldspar and high sodium iron and magnesium minerals, and the matrix is cryptic crystal. Often porphyritic texture, sometimes aphyric texture. A porphyritic texture, phenocrysts are mostly sodium orthoclase or sanidine and nepheline, nosean, leucite and other side feldspar minerals. According to the main feldspathoid minerals can be divided into Phonolite, Phonolite nosean nepheline and leucite Phonolite etc.. The rock was gray or dark gray, slightly fat luster. A small rocky Huoyan out abortion. If only nepheline one of the accessory feldspar, it can be called Phonolite; if the granlogite is the most abundant accessory feldspar, it is called the Phonolite (leucite phonolite), and so on.