10. granite rock type: igneous distinguishing features: completely crystallized, large, well formed interlocking crystals visible to the naked eye, no preferred crystal orientation, fairly light in color (white, gray, pink). main minerals quartz, feldspar, biotite weathering behavior : physical weathering can break the rock along its crystal boundaries
11. granite is an igneous rock that forms by slow cooling of silica-rich magma deep within the earth
13. basalt Basalt is an igneous rock that forms through rapid cooling at the surface of the earth. The island of hawaii, for example is almost entirely made from basaltic lava flows. weathering of iron minerals can turn the surface tan or reddish brown (see image below
21. basalt Basalt is a fine-grained, dark-colored extrusive igneous rock composed mainly of plagioclase and pyroxene. Basalt is also abundant on the moon!
30. Porphyritic rocks A theory of how porphyritic rocks are formed: Magma cools slowly deep inside the earth. Large crystals are able to form. THEN, the remaining liquid magma is pushed upward until close to the surface of the earth. Forms fine crystals.