Hornfels :
8. hornfels
Hornfels is a non-foliated, baked rock that is formed by contact metamorphism.
The color, grain size, and mineral composition shows wide variation.
Colors can range from a light gray to a dark black. The darkest colored varieties
of hornfels

igneous rocks

Granite is a light-colored igneous rock with grains large enough to be visible with the unaided eye. It forms from the slow crystallization of magma below Earth’s surface. Granite is composed mainly of quartz and feldspar with minor amounts of mica, amphiboles and other minerals. This mineral composition usually gives granite a red, pink, gray or white color with dark mineral grains visible throughout the rock.

  1. Pumice in its powdered or dust form, is a volcanic rock that consists of highly vesicular rough textured volcanic glass, which may or may not contain crystals. It is typically light colored.

Gabbro is a dark plutonic rock that is considered to be the plutonic equivalent of basalt. (more below)

Basalt is a common extrusive igneous (volcanic) rock formed from the rapid cooling of basaltic lava exposed at or very near the surface of a planet or moon. Flood basalt describes the formation in a series of lavabasalt flows.

Andesite is an extrusive rock intermediate in composition between rhyolite and basalt. Andesite lava is of moderate viscosity and forms thick lava flows and domes. The word andesite is derived from the Andes Mountains in South America, where andesite is common. Andesite is the diorite.




Metamorphic  rocks

Slate : Slate is metamorphosed shale. Slate is tougher than shale and it breaks into thin,
flat layers. Slate is usually dark gray, but it can also be red colored. Slate has been
used in some countries as roofing and more recently, it has been utilized as floor tiles.

Phyllite: Phyllite is metamorphosed slate.It is still foliated (layered), but unlike slate, the layers
are not completely flat but have a slightly
undulating pattern. Phyllite also has a slightly
silky appearance due to the growth of tiny mica plates oriented parallel to the foliation.

Marble :


Non-Foliated Metamorphic Rocks
5. marble
Marble is metamorphosed limestone. In the process of being metamorphosed, the
limestone is recrystallized, creating a change in color and texture and the destruction
of included fossils. There are hundreds of recognized commercial marble with a wide
range of colors and patterns. However, since marble is calcite, it still bubbles vigorously
when strong hydrochloric acid is applied to it.
The gray streaks in typical marble are
made up of graphite. Marble can range from white to pink to brown, and even black.
Limestones that have broken by tectonic forces as they are being metamorphosed
produce brecciated marbles. Cut and polished marble is used for statues and flooring.

Gneiss : is metamorphosed schist. It is a highly metamorphosed that is almost a granite.
It differs from schist due to the lenses of feldspar between the mica layers. The minerals
in gneiss may occur either as layers (foliation) or elongated in one direction (lineation).
Intensely crumpled layers are another means of identifying gneiss.

sedimtarey rocks

limestone : imestone is a sedimentary rock composed primarily of calcium carbonate (CaCO3) in the form of the mineral calcite. It most commonly forms in clear, warm, shallow marine waters. It is usually an organic sedimentary rock that forms from the accumulation of shell, coral, algal and fecal debris. It can also be a chemical sedimentary rock formed by the precipitation of calcium carbonate from lake or ocean water.

Coal (from the Old English term col, which has meant "mineral of fossilized carbon" since the 13th century)[1] is a combustible black or brownish-black sedimentary rock usually occurring inrock strata in layers or veins called coal beds or coal seams. The harder forms, such as anthracite coal, can be regarded as metamorphic rock because of later exposure to elevated temperature and pressure. Coal is composed primarily of carbon along with variable quantities of other elements, chiefly hydrogen, sulfur, oxygen, and nitrogen.[

chert is a sedimentary rock consisting almost entirely of silica (SiO2), and can form in a variety of ways. Biochemical chert is formed when the siliceous skeletons of marine plankton are  during quartz.

amber :
mber is the fossilized resin from ancient forests. Amber is not produced from tree sap, but rather from plant resin. This aromatic resin can drip from and ooze down trees, as well as fill internal fissures, trapping debris such as seeds, leaves, feathers and insects. The resin becomes buried and fossilized through a natural polymerization of the original organic compounds.

salt : Rock salt or Halite to give it it's proper name is a mineral formed from sodium chloride. It's chemical formula is NaCl and this also includes other variations of salt such as common salt and table salt. Rock salt tends to be the industrial name used for Halite.It forms as isometric crystals and is typically colorless or white but may also be other colours depending on the amount and type of impurities contained within it. The salt occurs in beds of sedimentary evaporite minerals. This is caused by large lakes and seas drying up. These salt beds can be hundreds of metres deep.



landforms :


dikes :
READ EDIT VIEW HISTORY FEEDBACKView All (2)Dike, in geology, tabular or sheetlike igneous body that is often oriented vertically or steeply inclined to the bedding of preexisting intruded rocks; similar bodies oriented parallel to the bedding of the enclosing rocks are called sills. A dike set is composed of several parallel dikes; when the number of dikes is large, the termdike swarm is used. Although dikes may range in size from a few centimetres to greater than 10 metres (30 feet) in width, they average between 0.3 and 6 metres (1 and 20 feet) wide. The length of a dike usually depends upon how far it can be traced across the surface; dikes can be up to hundreds of miles long. Dikes have a wide range of rock compositions. They commonly have a porphyritic texture, i.e.,larger crystals within a finer grained groundmass, indicating two periods ofcrystallization.

shield volcanoes : A shield volcano resembles the appearance of a Hawaiian warrior’s shield in that they have a low-angle profile. In almost all cases the comparison to a shield is done because the width of these volcanoes is typically around 20 times the size of their height. Despite this, they can vary greatly in terms of size with some having small diameters of a few kilometers while others can be over 95 kilometers. Some located in Hawaii reaching an altitude of 8,000 meters above the sea floor, which is 12,000 meters above their base. In fact, some of the largest volcanoes you will find on the planet are actually shield volcanoes, with Mauna Loa, located on Big Island in Hawaii, being the la.

caves : Marengo Cave U.S National Landmark.According to current geologic theory, Marengo Cave began to form approximately one million years ago. There is no documented evidence that anyone ever entered Marengo Cave before its historic discovery on September 6, 1883 by Orris and Blanche Hiestand, brother and sister, who lived in Marengo. The main corridors were quickly explored by Samuel Stewart’s son and his friends the following Sunday. Recognizing the value of what they had found, the Stewart’s immediately opened the cave to the public. The cave remained in the Stewart family until 1955. The present owners purchased the cavern in 1973 and have greatly expanded the operations.

geyser :eysers are Earth surface vents that periodically discharge a column of steam and hot water. Geysers greatly range in size and some of the larger geysers discharge thousands of gallons of boiling water into the air. This was can go hundreds of feet into the air. The world's most famous geyser is Old Faithful located inYellowstone National Park. Knowing the facts on geysers make these rare natural features even more magnificent.coincidence of unusual conditions is necessary for geysers to occur. Understanding how and why geysers occur is crucial in understanding why they are located where they are. The conditions required for geysers include.

composite volcanos :A composite volcano is also known as a stratovolcano. These volcanoes form tall, conical shaped mountains. Most of the Earth's active volcanoes have formed a ring around the Pacific Ocean. There are 452 stratovolcanoes in the Pacific Ring of Fire. The volcanoes are located in a volcanic arc on the continental side of subduction zones.

SILLS:A sill is a formation of igneous rock found in features such as mesas, hogbacks, and cuestas. Although sills can become exposed, sills are formed underground and are thus composed of plutonic igneous rocks . Sills are an intrusive rock formation. Intrusive formations such as dikes and sills are formed from magma that solidifies beneath the Earth's surface and then intrudes into the overlying host or country rock .