What do most igneous, sedimentary, and metamorphic rocks have in common? 1) They are formed from molten material. 2) They are produced by heat and pressure. 3) They are composed of minerals.

Differences. Metamorphic Rock – Forms when pressure, temperature, or chemical processes change existing rock. Igneous Rock – forms when magma or lava cools and hardens to become solid. Sedimentary Rock – Form when minerals that form from solutions or sediment from older rocks get pressed and cemented together.

One similarity between igneous rock and metamorphic rock, is they are both created under very hot temperatures. The difference between igneous rock and metamorphic rock is that igneous rocks are formed by the cooling and crystallization of magma, and metamorphic rocks form from heat and pressure.

Examples of aphanitic igneous rock include basalt, andesite andrhyolite. Glassy or vitreous textures occur during some volcanic eruptions when the lava is quenched so rapidly that crystallization cannot occur. The result is a natural amorphous glass with few or no crystals. Examples includeobsidian and pumice.

Igneous Rock Classification

Felsic minerals (quartz, K feldspar, etc) are light colored while mafic minerals (hornblende, pyroxenes) are normally dark colored. Felsic minerals have the lowest melting points (600 to 750 °C) and mafic minerals have higher melting points (1000 to 1200 °C).

Andesite is an extrusive rock intermediate in composition between rhyolite and basalt. Andesite lava is of moderate viscosity and forms thick lava flows and domes. The word andesite is derived from the Andes Mountains in South America, where andesite is common.

It is commonly but not exclusively of silicic or felsic to intermediate in composition (e.g., rhyolitic, dacitic, andesite, pantellerite, phonolite, trachyte), but basaltic and other compositions are known. Pumice is commonly pale in color, ranging from white, cream, blue or grey, to green-brown or black.

Granite is a coarse-grained igneous rock with average grain size ranging from 1 to 25 millimeters. Gabbro is generally coarse grained, with crystals in the size range of 1 mm or greater.

Intrusive igneous rocks like granite and gabbro have some things in common. They: Are large grained – magma cools very slowly beneath the Earth’s surface so the crystals in the rock have a long time to grow. 2.