Read this tip to make your life smarter, better, faster and wiser. LifeTips is the place to go when you need to know about Rocks and other Natural Science topics.
If a rock is made of randomly oriented crystals of different sizes, it's probably a plutonic igneous rock, one which cooled slowly far below the earth's surface.
Granite and granitic rocks (light-colored plutonic igneous rocks) often are made of three or more different minerals, so they are often a mixture of clear, white, pink, light gray, and a black minerals grains.
Diorite and other "intermediate" (not light, not dark) rocks are often made of clear, white, and dark minerals - the dark minerals are usually a higher percentage of the total rock than you find in granites.
Gabbro (dark-colored plutonic rock) will appear to be mostly dark minerals.
Guru Spotlight |
Susan Sayour |