All rocks from Geology class (wk9 quiz studying)

Basalt

Extrusive, mafic, formed at hot spots and in crust near spreading centers

Coal

Sedimentary. High in organic matter. Numerous thin layers/beds.

Conglomerate

Made of irregular chunks of other rock types — those other rocks can be identified specifically from the sample. Does not fizz when acid dropped on it.

Conglomerate

Contains many fragments of light-colored igneous rocks with large crystals in them. These fragments are all well-rounded and contain a dark-colored material between them all.

Conglomerate

Contains many well-rounded sedimentary rocks. Rock fizzes when acid dropped on it. The material between the sedimentary rocks is light-colored.

Fossiliferous sandstone

Contains sand-sized sediment. Numerous fossils. Probably reacts with acid bc of calcium carbonate presence.

Gabbro

Intrusive, mafic, formed under hot spots and in crust near spreading centers

Gneiss

A medium-grade, foliated metamorphic rock that has a banded appearance and is made up of granular mineral grains.

Granite

Felsic, intrusive, forms as batholiths when crust melts at subduction zone and then rises again

Graywacke

Sandstone with clay and silt particles mixed in with it. Sediments deposited by underwater landslides in a subduction trench.

Limestone

Rock is a uniform light color. No crystals or sediments visible within it. Rock fizzes when acid dropped on it. No layering visible.

Limestone

Rock contains tiny shell fragments, along with some sand. Fizzes vigorously when acid dropped on it. Light colored.

Limestone

Medium-gray rock with some obvious layering. No crystals visible. A few larger sediments within the rock. Fizzes when acid dropped on it.

Marble

A non-foliated metamorphic rock that is produced from the metamorphism of limestone. Contains calcite.

Obsidian

Volcanic glass -- formed extrusively. Dark in color; translucent near edges. Almost entirely SiO2.

Pumice

Light-colored rock. Many air pockets within it. No visible minerals or sediments present. Very low density.

Quartzite

a non-foliated metamorphic rock that is produced by the metamorphism of sandstone. It is composed primarily of quartz.

Rhyolite

Extrusive, felsic, forms at surface at stratovolcanoes

Sandstone

Contains sand-sized sediment. Original rocks that sediments eroded from were probably felsic, based on color of sediment grains.

Schist

A metamorphic rock with well developed foliation. It often contains significant amounts of mica which allows the rock to split into thin pieces, and which often gives the rock a shiney appearance. Usually grey or some variation of grey. It is a rock of intermediate metamorphic grade

Serpentinite

Blue-green rock. No minerals or sediments visible. Slippery to touch. Formed from metamorphosed mantle material.

Shale

A very fine-grained sedimentary rock, formed in a quiet depositional environment.

Slate

A foliated metamorphic rock that is formed through the metamorphism of shale. It is a low grade metamorphic rock that splits into thin pieces.