METAMORPHIC ROCK SPECIMEN
Rocks are simply defined as an aggregate of minerals. There three classifications Igneous Rocks formed from cooled lava and magma associated with volcanic activity. Sedimentary Rocks formed from compacting sediments (pebbles, sand and clay) often below sea level. Metamorphic Rocks forms from preexisting rocks that get buried and remain in a solid state while immersed at various levels of heat and pressure.
Metamorphic Rocks
Regional metamorphism is due to heat and pressure and produces foliation or cleavage in rocks where minerals have been aligned due to pressure and recrystallization.
Metamorphic Rocks: Foliated from regional metamorphism
Rock name: Black Slate.
Rock type: Metamorphic “to change form”.
Classification: “Foliated”.
Parent rock: Shale.
Metamorphism Grade: Very low.
Index Mineral: Graphite.
Human uses: Floor and roof tile.
Rock name: Red Slate.
Rock type: Metamorphic “to change form”.
Classification: “Foliated”.
Parent rock: Shale.
Metamorphism Grade: Very low.
Index Mineral: Graphite.
Human uses: Floor and roof tile.
Rock name: Graphic Slate.
Rock type: Metamorphic “to change form”.
Classification: “Foliated”.
Parent rock: Shale.
Metamorphism Grade: Very low.
Index Mineral: Graphite.
Collected: east of Llano, Texas at Honey Creek.
Rock name: Phyllite.
Rock type: Metamorphic “to change form”.
Classification: “Foliated”.
Parent rock: Slate.
Metamorphism Grade: Low.
Index Mineral: Talc and Chlorite.
Human uses: Source of Talc.
Collected: Interstate 10 west near American Talc Mine.
Rock name: Phyllite.
Rock type: Metamorphic “to change form”.
Classification: “Foliated”.
Parent rock: Slate.
Metamorphism Grade: Low.
Index Mineral: Talc and Chlorite.
Human uses: Source of Talc.
Collected: Interstate 10 west near American Talc Mine.
Rock name: Green Schist.
Rock type: Metamorphic “to change form”.
Classification: “Foliated”.
Parent rock: Phyllite, Granite, and Rhyolite.
Metamorphism Grade: Medium.
Index Mineral: Garnet.
Human uses: Decorative rock walls, decorative stone, and jewerly.
Rock name: Mica Schist.
Rock type: Metamorphic “to change form”.
Classification: “Foliated”.
Parent rock: Phyllite, Granite, and Rhyolite.
Metamorphism Grade: Medium.
Index Mineral: Garnet.
Human uses: Decorative rock walls, decorative stone, and jewerly.
Rock name: Mica Schist.
Rock type: Metamorphic “to change form”.
Classification: “Foliated”.
Parent rock: Phyllite, Granite, and Rhyolite.
Metamorphism Grade: Medium.
Index Mineral: Garnet.
Human uses: Decorative rock walls, decorative stone, and jewerly.
Rock name: Garnet Schist.
Rock type: Metamorphic “to change form”.
Classification: “Foliated”.
Parent rock: Phyllite, Granite, and Rhyolite.
Metamorphism Grade: Medium.
Index Mineral: Garnet.
Human uses: Decorative rock walls, decorative stone, and jewerly.
Rock name: Folded Gneiss.
Rock type: Metamorphic “to change form”.
Classification: “Foliated”.
Parent rock: Schist, Granite, and Rhyolite.
Metamorphism Grade: High.
Index Mineral: Corundum.
Human uses: Countertops (often sold as “Granite”).
Rock name: Banded Gneiss.
Rock type: Metamorphic “to change form”.
Classification: “Foliated”.
Parent rock: Schist, Granite, and Rhyolite.
Metamorphism Grade: High.
Index Mineral: Corundum.
Human uses: Countertops (often sold as “Granite”).
Rock name: Banded Gneiss.
Rock type: Metamorphic “to change form”.
Classification: “Foliated”.
Parent rock: Schist, Granite, and Rhyolite.
Metamorphism Grade: High.
Index Mineral: Corundum.
Human uses: Countertops (often sold as “Granite”).
Rock name: Gneiss with dike intrustion.
Rock type: Metamorphic “to change form”.
Classification: “Foliated”.
Parent rock: Schist, Granite, and Rhyolite.
Collected: Northside of the Lano Bridge in Llano, Texas.
Human uses: Countertops.
Rock name: Migmatite.
Rock type: Metamorphic “to change form”.
Classification: “Foliated”.
Parent rock: Gneiss, Granite, and Rhyolite.
Metamorphism Grade: Very high.
Human uses: Countertops (often sold as “Granite”).
Rock name: Migmatite.
Rock type: Metamorphic “to change form”.
Classification: “Foliated”.
Parent rock: Gneiss, Granite, and Rhyolite.
Metamorphism Grade: Very high.
Human uses: Countertops (often sold as “Granite”).
Metamorphic Rocks: Non foliated from contact metamorphism
Rock name: Fine Grain Marble.
Rock type: Metamorphic “to change form”.
Classification: “non-foliated”.
Parent rock: Limestone.
Composition: CaCO3.
Human uses: Statues, walls, floors and countertops.
Rock name: Course Grain Marble.
Rock type: Metamorphic “to change form”.
Classification: “non-foliated”.
Parent rock: Limestone.
Composition: CaCO3.
Human uses: Statues, walls, floors and countertops.
Rock name: Polished Fine Grain Marble.
Rock type: Metamorphic “to change form”.
Classification: “non-foliated”.
Parent rock: Limestone.
Composition: CaCO3.
Human uses: Statues, walls, floors and countertops.
Rock name: Fine Grain Quartzite.
Rock type: Metamorphic “to change form”.
Classification: “non-foliated”.
Parent rock: Sandstone.
Composition: SiO2.
Human uses: Train track gravel.
Rock name: Course Grain Quartzite.
Rock type: Metamorphic “to change form”.
Classification: “non-foliated”.
Parent rock: Sandstone.
Composition: SiO2.
Human uses: Train track gravel.
Rock name: Serpentinite.
Rock type: Metamorphic “to change form”.
Classification: “non-foliated”.
Parent rock: Basalt.
Origin: Metasomatism (wet metamorphism).
Human uses: Train track gravel.
Rock name: Metaconglomerate.
Rock type: Metamorphic “to change form”.
Classification: “non-foliated”.
Parent rock: Conglomerate.
Human uses: Kitchen countertops.
Rock name: Metabreccia.
Rock type: Metamorphic “to change form”.
Classification: “non-foliated”.
Parent rock: Breccia.
Human uses: Kitchen countertops.
Rock name: Anthracite.
Rock type: Metamorphic “to change form”, sometimes classified as sedimentary.
Classification: “non-foliated”.
Parent rock: Coal.
Human uses: Burned simialer to coal.
Data: Pellant, Chris. Smithsonian Handbooks. Rocks and Minerals: The clearest recognition guide available. A Dorling Kindersley Book.