Rocks

Greywacke is variation of sandstone that saperate from other to hardness, dark color, and poorly sorted angular grains of quartz and feldspar. Generally found in Palezoic strata. Generally larger grain can be sand clast. Matrix material more than 15%.

Diorite is coarse – grained intrusive igneous rock that commonly mineralogy is plagioclase feldspar and dark colored minerals such as hornblende and biotite.It usually occurs dikes, sills and intrusions with continental crust . Diorite is usually grey to dark-grey in colour, but it can also be black or bluish-grey, and frequently has a greenish cast.

Obsidian is an igneous rock that forms when molten rock material cools so rapidly that atoms are unable to arrange themselves into a crystalline structure. It is an amorphous material known as a "mineraloid." The result is a volcanic glass with a smooth uniform texture that breaks with a conchoidal fracture .

An important rock-forming mineral, dolomite is named after the French mineralogist Déodat Gratet de Dolomieu. It is a colorless to white, pale brown, grayish, reddish, or pink mineral. Its crystals are commonly rhombohedral or tabular, often have curved faces, and sometimes cluster in saddle-shaped aggregates.

A granular metamorphic rock, marble is derived from limestone or dolomite. It consists of a mass of interlocking grains of calcite or the mineral dolomite. Marbles form when limestone buried deep in the older layers of Earth’s crust is subjected to heat and pressure from thick layers of overlying sediments.

The most common intrusive rock in Earth’s continental crust, granite is familiar as a mottled pink, white, gray, and black ornamental stone. It is coarse- to medium-grained. Its three main minerals are feldspar, quartz, and mica, which occur as silvery muscovite or dark biotite or both. Of these minerals

Slate is a fine-grained, foliated metamorphic rock this is created via the alteration of shale or mudstone by means of low-grade local metamorphism. It is famous for a extensive form of makes use of such as roofing, floors, and flagging due to its sturdiness and appealing look.

Schist is medium grade metamorphic rock, formed by means of the metamorphosis of mudstone / shale, or some forms of igneous rock, to a higher diploma than slate, i.E. It has been subjected to better temperatures and pressures.

Quartzite is a nonfoliated metamorphic rock composed almost absolutely of quartz. It paperwork while a quartz-rich sandstone is altered via the warmth, pressure, and chemical interest of metamorphism. These situations recrystallize the sand grains and the silica cement that binds them collectively. The result is a network of interlocking quartz grains of incredible power.

Hornfels is a fine-grained metamorphic rock These properties are because of first-class grained non-aligned crystals with platy or prismatic behavior. Hornfels is the group designation for a series of contact metamorphic rocks which have been baked and indurated by means of the warmth of intrusive igneous loads and had been rendered massive, difficult, splintery, and in a few cases exceedingly tough and sturdy.

Gneiss is a foliated metamorphic rock ,Is a common dispensed type of rock shaped by high-grade regional metamorphic approaches from pre-current formations that have been initially both igneous or sedimentary rocks Gneiss, metamorphic rock that has a awesome banding, which is apparent in hand specimen or on a microscopic scale.

Amphibolite, a rock composed in large part or dominantly of minerals of the amphibole institution. The term has been implemented to rocks of both igneous or metamorphic foundation. In igneous rocks, the term hornblendite is greater not unusual and restrictive; hornblende is the maximum not unusual amphibole and is traditional of such rocks.