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.

(1−3) Obsidian is characterized by its rigid, glassy composition with a brittle and amorphous texture, featuring razor-sharp edges due to the rapid cooling of silica-rich felsic igneous rocks (making ...

An igneous rock has come to be regarded, more constantly than before, not merely as a mineral-aggregate, but as-the product of consolidation of a molten rock-magma; and consideration has been ...