Which one of the following is an example of both an igneous as well as a metamorphic rock?

Correct option is C

The correct answer is (c) Gneissoid. Explanation: Gneissoid is a type of rock that has characteristics of both igneous and metamorphic rocks. Gneiss is a metamorphic rock formed from the metamorphism of igneous rocks like granite or sedimentary rocks. When igneous rocks undergo extreme heat and pressure, they are transformed into gneiss, which gives the term gneissoid its dual characteristic. Information Booster: Igneous Rocks: · Formation: From cooling of magma or lava. · Intrusive (e.g., Granite): Formed beneath the Earth’s surface (slow cooling, larger crystals). · Extrusive (e.g., Basalt): Formed on the Earth’s surface (quick cooling, smaller crystals). · Characteristics: Hard, dense, often with visible crystals. Metamorphic Rocks: · Formation: From existing rocks (igneous or sedimentary) undergoing extreme heat, pressure, or chemical changes. · Types: · Foliated (e.g., Gneiss): Layered due to pressure. · Non-foliated (e.g., Marble): No distinct layers. · Characteristics: Harder and more resistant than the original rock. Transformation: · Granite (igneous) can turn into gneiss (metamorphic) under heat and pressure.