Rocks

Diatomite, also known as diatomaceous earth, is a naturally occurring, soft, siliceous sedimentary rock that is easily crumbled into a fine white to off-white...

Chert is a microcrystalline or cryptocrystalline sedimentary rock cloth composed of silicon dioxide (SiO2). It takes place as nodules, concretionary hundreds, and as layered deposits. Chert breaks with a conchoidal fracture, often producing very sharp edges. Early people took advantage of the way chert breaks and used it to fashion cutting equipment and weapons. The name "flint" is also used for this fabric.

Flint is a naturally occurring sedimentary rock composed primarily of microcrystalline quartz, or silicon dioxide (SiO2). It is renowned for its historical significance and...

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.

Breccia is a rock shaped from angular gravel and boulder-sized clasts cemented collectively in a matrix. The angular nature of the clasts suggests that they have now not been transported very far from their source. There are numerous modes of formation for breccia. Some constitute consolidated material accumulated on steep hill slopes or on the foot of cliffs.

Tinguaite is a type of volcanic rock, primarily composed of nepheline and alkali feldspar, with lesser amounts of other minerals such as amphibole, biotite,...

Gabbro is a type of intrusive igneous rock that is coarse-grained and dark-colored, typically composed of calcium-rich plagioclase feldspar, pyroxene, and sometimes olivine. It...

Kakortokite is a rare, layered peralkaline intrusive igneous rock dominated by perthitic microcline feldspar, with significant amounts of nepheline and characteristic eudialyte-rich layers.It is...

An intrusive igneous rock, peridotite is coarsegrained and dense. It is light to dark green in color. Peridotite contains at least 40 percent olivine and some pyroxene. Unlike the olivine grains, the pyroxene grains in peridotite have a visible cleavage when viewed under a hand lens. Peridotite forms much of Earth’s mantle and can occur as nodules that are brought up from the mantle by kimberlite or basalt magmas.

Fossiliferous limestone is a type of sedimentary rock that contains abundant fossils. It is formed through the accumulation and compression of organic remains, such...

The Metamorphic Rock Shaped by Heat, Pressure and TimeQuartzite is one of the hardest and most durable metamorphic rocks on Earth. Its origin is...

Monzonite is a type of igneous rock that falls within the category of intrusive or plutonic rocks. It is primarily composed of minerals such...