How are Granite and Marble different?
Marble is a metamorphic rock. It was once limestone, but over time, the combination of intense heat and pressure caused the limestone to re-crystallize. Foreign substances often entered the stone during this process, creating an infinite variety of colors, asters, and veining. Marble is a lot like snowflakes, no two pieces are exactly alike. Granite is an igneous rock, which means that at one time during its development, it was melted like volcanic lava. Unlike lava, however, this melted (or molten) rock never reached the surface. It remained trapped inside, where it slowly cooled and crystallized, resulting in a very uniform, speckled stone that ranges in color from black and gray tones to pinks, browns, and reds.
