24 specimens, 1 1/4", including six each of the following: rock-forming minerals, igneous, sedimentary and metamorphic rocks. Also includes a study guide.
ROCK AND ROCK-FORMING MINERALS
ROCK-FORMING MINERALS
Minerals are naturally occurring chemical compounds or elements found in the earth's crust and are the building blocks of rocks. Rocks may contain only a single mineral, but usually they contain a mixture of many minerals.
1. Quartz - Silicon dioxide, or quartz, is the most common mineral in the earth's crust.IGNEOUS ROCKS
Igneous rocks were once lava or magma, that is, a molten collection of minerals. The rate at which a lava or magma cools and solidifies influences rock texture, making it either fine, medium or coarse grained.
7. Pumice - A light colored volcanic rock of rhyolitic composition; the texture results from bubbles formed by escaping gasses.METAMORPHIC ROCKS
Metamorphic rocks are rocks that have been changed (metamorphosed), by heat, pressure, and/or hydrothermal solutions. All three rock types can be metamorphosed.
13. Mica Schist - This rock is a highly metamorphosed shale. All schists exhibit shistose structure; the generally parallel alignment of micaceous minerals.SEDIMENTARY ROCKS
Clastic sedimentary rocks are formed from layers of sediment (fragments of older, weathered rock) exposed to pressure. Other sedimentary rocks are of organic or chemical origin.
19. Sandstone - Quartz grains cemented together by silica, calcite or other cementing minerals make up this clastic, sedimentary rock.