Presentation on theme: "Igneous Rock.... Two types of molten rock: Igneous Rocks Felsic Mafic High in silicates Low in silicates slow flowing light color fast flowing dark color."— Presentation transcript:
Above the surface − Extrusive or volcanic. − Cools and solidifies quickly. − Crystals with small grain size or no crystals at all (glass). − Can also show air gaps from bubbles. Relatively light. Igneous Rocks Form in 2 places:
Igneous Rocks Below the surface − Called intrusive or plutonic. − Cools and solidifies slowly. − Shows crystals with large grain size.
Igneous Rocks Descriptive Terminology of Rock Texture Texture: the size, shape, and arrangement of the mineral crystals in the rock. Porphyry: Large crystals are surrounded by a fine-grained mass of rock. It can also have bubbles. Frothy: Rocks with no crystals/minerals visible. Has many air gaps (bubbles) and has a foamy appearance.
Igneous Rocks Descriptive Terminology of Rock Texture Fine Grain: Small, barely visible crystals. Seen with the aid of a magnifying glass. Coarse Grain: Large crystals, visible with the un-aided eye, of various minerals in the rock together. Glassy: Rocks with no crystals and a clear or translucent appearance.