Just a few minerals make up most of the rocks we see, though: feldspars, amphiboles, quartz, olivine ... grains of other rocks and organic matter. Metamorphic rocks are the third main classification.

Agate collecting is a fascinating and rewarding hobby that attracts enthusiasts from all walks of life With its myriad of colours patterns and forms agate is one of the most diverse and sought-after g ...

and they are usually derived from igneous and metamorphic rocks in soil (Lapidus 1987). In most soils, feldspars, micas, and quartz are the main primary mineral constituents, and pyroxenes and ...

What FACTS ABOUT ROCKS do you know? They are abundant on earth, and yet little is known about them. These facts will increase your knowledge of the rocks.