Igneous rock (from the Latin word ignis for fire) is one of the three main types of rocks (the others being sedimentary and metamorphic rocks). It forms when molten magma inside the Earth, near active plate boundaries or hotspots, rises towards the surface and cools. During the cooling process, mineral crystals and sometimes glass solidify from the magma, giving rise to a solid rock structure.

Objective: The upcoming exercises aim to acquaint you with the compositions and cooling histories of igneous rocks. You will learn to identify common igneous rocks based on their color and texture, discern the mineral composition of these rocks, and understand the correlations between igneous rock compositions and tectonic settings.

Learning Goals: Upon completion of this lab, you will:

Understand the formation of igneous rocks underground and above ground.

Determine the cooling history of igneous rocks based on rock texture.

Ascertain the composition of igneous rocks based on rock color.

Recognize how igneous rocks with the same composition but different cooling histories exhibit varied textures while maintaining the same mineral distribution.

Comprehend the relationship between igneous rock composition and tectonic setting. You may encounter new terms and concepts throughout these exercises. Don`t fret; you will delve deeper into these topics later in the course. Focus on grasping the fundamental concepts, and feel free to reach out if you require clarification on any term or concept.