Dacite

Classification：Igneous Rock

A felsic volcanic extrusive rock, mainly composed of feldspar and quartz, is commonly found in the subduction zone of active continental margin.

Dacite is an intermediate acid extrusive rock, belonging to volcanic rocks, which is equivalent to granodiorite ejecta. In China, it is mainly produced in the southeast coastal areas. Dacite often interacts with rhyolite, trachyte and andesite, forming huge thick volcanic rocks. The chemical composition and mineral composition and granodiorite and quartz diorite is the volcano rock flash. Porphyritic texture, phenocrysts are plagioclase neutral, alkaline plagioclase is less, sometimes with a small amount of quartz. Usually the glass structure, hyalopilitic texture or felsitic structure. Xie Changshi (Ordovician to middle feldspar), quartz, augite or ordinary amphibole. Porphyritic structure and rhyotaxitic structure. The matrix is composed of fine feldspar and quartz.

Basic features:
The chemical composition and mineral composition and granodiorite and quartz diorite is the volcano rock flash. It is characterized by light color: gray or gray. Porphyritic texture, phenocrysts are plagioclase neutral, alkaline plagioclase is less, sometimes with a small amount of quartz. The matrix is fine-grained feldspar, quartz and so on. Usually the glass structure, hyalopilitic texture or felsitic structure. Some with rhyolitic structure. Dacite often interacts with rhyolite, trachyte and andesite, forming huge thick volcanic rocks. Volcanic areas in China are all exposed, especially in southeastern coastal areas. Dacite related minerals are montmorillonite, kaolinite, alunite, pyrophyllite, pyrite and fluorite etc.

Main minerals:
Xie Changshi (Ordovician to middle feldspar), quartz, augite or ordinary amphibole. They can appear as phenocrysts (coarse grained) in fine or vitreous matrix. If we do not identify with microscope, Dacite is a light colored rock which is difficult to distinguish from rhyolite.
Its mineral composition and chemical composition are similar to granodiorite or quartz diorite. Gray or gray.
Porphyritic structure and rhyotaxitic structure. Most of the phenocrysts are neutral plagioclase, with less alkaline feldspar and sometimes a small amount of quartz.
The matrix is composed of fine feldspar and quartz.
It is often associated with rhyolite, trachyte, andesite and quartz porphyry, and is composed of thick volcanic rocks.
Its related minerals include pyrite, alunite, montmorillonite and kaolinite.