Metamorphic rocks what is it

Anthracite is the highest rank of coal. It has been exposed to enough heat and pressure that most of the oxygen and hydrogen have been driven off, leaving a high-carbon material behind. It has a bright, lustrous appearance and breaks with a semi-conchoidal fracture. It is often referred to as "hard coal"; however, this is a layman's term and has little to do with the hardness of the rock. Hornfels is a fine-grained nonfoliated metamorphic rock with no specific composition. It is produced by contact metamorphism.

Hornfels is a rock that was "baked" while near a heat source such as a magma chamber , sill , or dike. Marble is a non-foliated metamorphic rock that is produced from the metamorphism of limestone or dolostone. It is composed primarily of calcium carbonate. Lapis Lazuli , the famous blue gem material, is actually a metamorphic rock. Most people are surprised to learn that, so we added it to this photo collection as a surprise.

Blue rocks are rare, and we bet that it captured your eye. Novaculite is a dense, hard, fine-grained, siliceous rock that breaks with a conchoidal fracture. It forms from sediments deposited in marine environments where organisms such as diatoms single-celled algae that secrete a hard shell composed of silicon dioxide are abundant in the water.

The specimen shown above is about three inches across. Mariposite is a word that has been used in many ways. It can refer to green mica minerals, or metamorphic rocks that contain enough green mica to impart a green color.

Gold prospectors learned that gold could be found in areas where these green rocks were present. This is because mariposite is an ore of gold.

Quartzite is a non-foliated metamorphic rock that is produced by the metamorphism of sandstone. It is composed primarily of quartz. The specimen above is about two inches five centimeters across. Phyllite is a foliated metamorphic rock that is made up mainly of very fine-grained mica. The surface of phyllite is typically lustrous and sometimes wrinkled. Because it has been squeezed harder than slate it is often found folded and crumpled. Schists are usually named by the main minerals that they are formed from.

Bitotite mica schist, hornblende schist, garnet mica schist, and talc schist are some examples of this. Gneiss is a high grade metamorphic rock. This means that gneiss has been subjected to more heat and pressure than schist. Gneiss is coarser than schist and has distinct banding. This banding has alternating layers that are composed of different minerals. The minerals that compose gneiss are the same as granite.

Feldspar is the most important mineral that makes up gneiss along with mica and quartz. Gneiss can be formed from a sedimentary rock such as sandstone or shale, or it can be formed from the metamorphism of the igneouse rock grantite.

Gneiss can be used by man as paving and building stone. Non-Foliates are metamorphic rocks that have no cleavage at all. Quartzite and marble are two examples of non-foliates that we are going to study. Quartzite is composed of sandstone that has been metamorphosed. Quartzite is much harder than the parent rock sandstone.

It forms from sandstone that has come into contact with deeply buried magmas. Quartzite looks similar to its parent rock. The best way to tell quartzite from sandstone is to break the rocks.

Sandstone will shatter into many individual grains of sand while quartzite will break across the grains. Marble is metamorphosed limestone or dolomite. Both limestone and dolomite have a large concentration of calcium carbonate CaCO3. Marble has many different sizes of crystals. Marble has many color variances due to the impurities present at formation. Some of the different colors of marble are white, red, black, mottled and banded, gray, pink, and green. Marble is much harder than its parent rock.

This allows it to take a polish which makes it a good material for use as a building material, making sink tops, bathtubs, and a carving stone for artists. Today, headstones are made from marble and granite because both of these rocks weather very slowly and carve well with sharp edges. Write the answers to the following questions in complete sentences on a piece of paper. Write a definition in your own words of what a metamorphic rock is.

What are the three agents of metamorphism? What are the three types of metamorphism? In your own words write a definition of the rock cycle. Skip to main content. Toggle menu Go to search page. Search Field.

Metamorphic Rocks Lesson These factors are; 1. Hornfels rocks are metamorphic rocks. They usually start out as sedimentary rocks like sandstone or shale, but then volcanic material pushes up from below and bakes the sedimentary rock into a metamorphic one. Hornfels are known for being exceptionally tough and durable. This one is from Chantilly, VA. USGS scientist Art Bookstrom looks at puzzling sedimentary structures in metasedimentary rocks of the Apple Creek Formation, near the Jackass prospect, near Iron Creek, in the southeastern part of the Idaho cobalt belt, in east-central Idaho.

Intensely fractured Proterozoic metamorphic basement rock exposed in Poncha Canyon. Systematic structural measurements of fractures in such old rocks indicate a protracted history of brittle deformation in the core of Poncha mountain block that continued into recent rift-related extensional faulting. Outcrop of biotitic meta-sandstone in the lower part of the Gunsight Formation, cut by white quartz veins with alteration envelopes of coarsely crystalline black biotite and minor muscovite.

Skip to main content. Search Search. Apply Filter. It is smoothly rounded on three sides and a sheer vertical face on the fourth. Half Dome, which stands nearly 8, feet 2, meters above sea level, is composed of granodiorite, and is the remains of a magma chamber that cooled slowly and crystallized Is glacier ice a type of rock? Glacier ice, like limestone for example , is a type of rock.

Glacier ice is actually a mono-mineralic rock a rock made of only one mineral, like limestone which is composed of the mineral calcite. The mineral ice is the crystalline form of water H 2 O. Most glacier ice forms through the metamorphism of tens of thousands of individual What are sedimentary rocks? Sedimentary rocks are formed from pre-existing rocks or pieces of once-living organisms. They form from deposits that accumulate on the Earth's surface.

Sedimentary rocks often have distinctive layering or bedding. Many of the picturesque views of the desert southwest show mesas and arches made of layered sedimentary rock. Common Sedimentary Rocks Are there geologic maps or publications for where I live? Detailed geologic mapping has not been completed for the entire United States, but maps are available for most locations. Geologic maps at many scales and from many sources are listed in the National Geologic Map Database.

Download digital geologic maps for entire states Where can I find information about the geology and natural history of National Parks? Our National Parks are the showcases of our nation's geological heritage.