rochas

Rochas are naturally occurring solid aggregates composed of minerals. In geology, rochas (plural) refer to the bodies that make up most of the Earth’s crust. Rocks are broadly classified by origin into three categories: igneous, sedimentary, and metamorphic. Igneous rocks form by the cooling and solidification of molten material, either beneath the surface as plutonic rocks or on the surface as volcanic rocks. Sedimentary rocks form by lithification of sediments derived from weathering and erosion, or by precipitation of minerals from water. Metamorphic rocks arise when existing rocks are altered by heat, pressure, or chemically active fluids, typically without melting.

The texture and composition of rocks vary. Igneous rocks are described by mineral content (felsic to mafic) and grain size; sedimentary rocks by grain cementation and original structures; metamorphic rocks by foliation or mineral banding. Common examples include igneous granite and basalt; sedimentary sandstone, limestone, and shale; metamorphic marble, schist, and gneiss. The properties of rocks, such as hardness, porosity, and strength, influence their use in construction, manufacture, and design, as well as their behavior in weathering and erosion.

Rocks are central to geological research and resource management. They record past environmental conditions in fossils and sedimentary structures and host mineral resources such as ores and, in some formations, fossil fuels. The rock cycle describes the continual transformation of rocks through melting, solidification, weathering, lithification, and metamorphism driven by plate tectonics and surface processes. In Portuguese, rochas is the plural form of rocha; Rocha is a common surname and toponym.