Rocks

Aphanitic texture is one of the common igneous rock textures, especially volcanic rocks. It forms almost entirely through the physics

Gabbro is a coarse-grained (phaneritic), mafic intrusive igneous rock. It forms when iron- and magnesium-rich magma cools slowly beneath the

Norite is a mafic, coarse-grained, plutonic igneous rock composed predominantly of orthopyroxene and calcic plagioclase feldspar. It forms deep in

The questions that this post on scoria vs. pumice will tackle are: What does scoria have in common with pumice,

Pumice is an extremely low density, frothy, form-like or highly vesicular volcanic rock with a glass texture. This rock is

Rhyolite is a fine-grained to glassy, light-colored, silica-rich extrusive volcanic rock that often has a porphyritic texture. It forms when

Norite is a coarse-grained plutonic rock with mainly calcic plagioclase, orthopyroxene, and a minor amount of other minerals. Plutonic rocks

Obsidian uses include making prehistoric stone tools. Photo credit: Ismoon (talk) 21:26, 8 June 2018 (UTC), CC BY-SA 4.0, via Wikimedia Commons.

Dacite is a fine-grained, light-colored volcanic rock with a felsic composition. Felsic rocks are silica-rich and dominated by light-colored elements

Dacite and andesite are both fine-grained volcanic and extrusive igneous rocks. Volcanic or extrusive igneous rocks form when magma cools