Explanation
An acid extrusive rock with composition equivalent to granite. It appears as light gray white, light gray, white, greyish red, and light purple. They are usually aphanitic texture and porphyritic texture, and some are glassy and spheroidal texture with obvious flow structure, sometimes with banded or vesicular structure. The main mineral components are feldspar and quartze, the content of which can reach more than 90%. feldspar mainly consists of transparent feldspar and acid plagioclase, sometimes askew feldspar, and biotite or hornblende within 10%. feldspar and quartze often form phenocryst, and the content of phenocryst can reach more than 30%, which is called porphyry. If phenocryst are mainly crooked feldspar, alkaline pyroxene and alkaline amphibole, they are called alkali flow rocks. The minerals related to rhyolite are mainly non-metallic minerals, such as zeolite, alunite, pyrophyllite, kaolinite, montmorillonite and fluorite. The formation of some pyrite is also related to rhyolite. The compressive strength of fresh rhyolite is 150-300MPa, which is an ideal building stone. Fresh rhyolite with rhyolite or special spherical structure is also a high-quality decorative stone. In 1982, a barium rich rhyolite was discovered in Sichuan Province, China, which is closely related to polymetallic minerals.
Classification
Natural materials and products -> Mineral materials