Dacite from the Lassen Volcano National Park. Dacite (/ ˈ d eɪ s aɪ t /) is a volcanic rock formed by rapid solidification of lava that is high in silica and low in alkali metal oxides.It has a fine-grained to porphyritic texture and is intermediate in composition between andesite and rhyolite.It is composed predominantly of plagioclase feldspar and quartz. ...

英安岩 (Dacite)是一种中酸性喷出岩，属火山岩，相当于花岗闪长岩的喷出物。在中国，主要产于东南沿海各地。

Dacit. Dacitul este o rocă magmatică. Conține mult bioxid de siliciu. Dacitul și brecia sunt singurele rocu care conțin aur microscopic.

dacite, volcanic rock that may be considered a quartz-bearing variety of andesite.Dacite is primarily associated with andesite and trachyte and forms lava flows, dikes, and sometimes massive intrusions in the centres of old volcanoes. Like andesite, dacite consists mostly of plagioclase feldspar with biotite, hornblende, augite, or enstatite and generally has a porphyritic structure (scattered ...

QAPF Diagram for Dacite: A QAPF diagram is a method of classifying igneous rocks on the relative abundance of quartz, alkali feldspar, plagioclase feldspar, and feldspathoid minerals. The first letter of each of these minerals / mineral groups is the source of the "QAPF" name used for the diagram. Before plotting the composition of a rock on the diagram, the percentages of the QAPF minerals ...

2023年9月14日 · Quick properties and characteristics. Rock name: Dacite Rock type: Igneous Origin: Extrusive or volcanic Color: White, gray, pink, brownish, blue-gray, yellow, or reddish Texture: Fine-grained or aphanitic to porphyritic Chemical composition: Felsic Silica content: 63-69 wt. % Plutonic or coarse-grained equivalent: Granodiorite Eruption temperature: ≈900-1000°C at …

2024年5月10日 · Description and Appearance. Dacite is a massive, hard, fine-grained, light-colored rock with 2.3-2.7 g/cm 3 (non-vesiculated type) and a Mohs hardness scale of 6 to 7.. Its color is off-white, gray, pinkish, or blue-gray, with few …

Dacite is an extremely common rock type, but many people have never even heard of it. Chances are good that you have seen and touched dacite many times in your life, whether or not you were aware of it at the time. It comes in many varieties, and it is worth learning more about due …

Dacitic rocks with felsics comprising >20% quartz and alkali feldspar/plagioclase <0.5. A fine-grained extrusive rock with a similar general composition to andesite, but having a more sodic plagioclase and more K-feldspar and quartz; it is the extrusive equivalent of granodiorite. Synonym: quartz andesite.

Dacite Dacite, from Dacia, a Roman province, Transylvania, Romania, is a volcanic rock that may be considered a quartz-bearing variety of andesite.