Andesite may be aphanitic or porphyritic.
It is glassy.
*fine-grained *coarse-grained
Porphryitic igneous rock is composed of phenocrysts embedded in a finer matrix.
By definition, yes. In contrast, aphanitic rocks do not have visible crystals.
No, not all lava crystallizes to form igneous rocks with phaneritic textures. Phaneritic textures are characterized by large, visible crystals, which form when magma cools slowly beneath the Earth's surface. Lava that cools quickly on the Earth's surface forms igneous rocks with aphanitic textures, characterized by fine-grained or glassy structures.
It is glassy.
*fine-grained *coarse-grained
Granite is a phaneritic rock. Phaneritic rocks are coarse-grained, and they have visible crystals. Other phaneritic rocks include diorite, gabbro, and periodite. These rocks are also intrusive because they cool slowly.
Porphryitic igneous rock is composed of phenocrysts embedded in a finer matrix.
By definition, yes. In contrast, aphanitic rocks do not have visible crystals.
Both andesite and diorite are igneous rocks with an intermediate color index. Diorite; however, is intrusive and phaneritic, whereas andesite is aphanitic and extrusive. Andesite is said to be the extrusive equivalent of diorite. Diorite is made up of plagioclase feldspar and ferromagnesian mineral crystals, mainly amphibole. Contrarily, andesite may resemble rhyolite, meaning it presents a need for microscopic examination to see its mineral crystals. The two have a composition of plagioclase feldspar and amphibole, but it is much more difficult to detect in andesite.
No, not all lava crystallizes to form igneous rocks with phaneritic textures. Phaneritic textures are characterized by large, visible crystals, which form when magma cools slowly beneath the Earth's surface. Lava that cools quickly on the Earth's surface forms igneous rocks with aphanitic textures, characterized by fine-grained or glassy structures.
And their texture, which can be aphanitic, phaneritic, glassy, or porphyritic. mineral composition and crystal texture
Phaneritic texture refers to igneous rocks that have large, visible crystals, typically formed from slow cooling of magma beneath the Earth's surface. In contrast, aphanitic texture describes rocks with small, fine-grained crystals that are not easily visible to the naked eye, indicating rapid cooling of lava at or near the surface. The size of the crystals in these textures provides insights into the cooling history and environment of the rock formation.
Phaneritic rock has visible identifiable crystal grains. Aphanitic rock has crystal grains that are too small to be visible with the naked eye. In igneous rock, the difference is due to the amount of time spent in cooling. Long term cooling of magma underground leads to large crystals, rapid cooling of lava above ground leads to small crystal texture.
These are called vesicles, which are voids left by gas bubbles escaping from magma as it solidifies. They are commonly seen in aphanitic rocks like basalt and andesite.
Rocks with an aphanitic texture have fine-grained crystals that are too small to be seen by the naked eye. Common igneous rocks with this texture include basalt, andesite, and rhyolite. These rocks cool quickly at the Earth's surface, preventing larger crystals from forming.