| Foliated Metamorphic Rocks | ||||
|---|---|---|---|---|
| Crystal Size | Mineralogy | Protolith | Metamorphism | Rock Name |
| very fine | clay minerals | shale | low grade regional | slate |
| fine | clay minerals, biotite, muscovite | shale | low grade regional | phyllite |
| medium to coarse | biotite, muscovite, quartz, garnet, plagioclase | shale, basalt | medium grade regional | schist |
| medium to coarse | amphibole, plagioclase, biotite | basalt | medium grade regional | amphibolite (Note: may be unfoliated) |
| medium to coarse | plagioclase, orthoclase, quartz, biotite, amphibole, pyroxene | basalt, granite, shale | high grade regional | gneiss |
| Unfoliated Metamorphic Rocks | ||||
| Crystal Size | Mineralogy | Protolith | Metamorphism | Rock Name |
| fine to coarse | quartz | sandstone | regional or contact | quartzite |
| fine to coarse | calcite | limestone | regional or contact | marble |
| fine | pyroxene, amphibole, plagioclase | shale | contact | hornfels |
Note that not all minerals listed in the mineralogy column will be present in every rock of that type and that some rocks may have minerals not listed here.
Geology 101 - Introduction to Physical Geology
Basics Table--Metamorphic Rock Classification
Created by Ralph L. Dawes, Ph.D. and Cheryl D. Dawes, including figures unless otherwise noted
updated: 9/16/13
Basics Table--Metamorphic Rock Classification
Created by Ralph L. Dawes, Ph.D. and Cheryl D. Dawes, including figures unless otherwise noted
updated: 9/16/13
Unless otherwise specified, this work by Washington State Colleges is licensed under a Creative Commons Attribution 3.0 United States License.