Rock (geology)
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In geology, a rock is any naturally occurring solid mass or aggregate of minerals or mineraloid matter. It is categorized by the minerals included, its chemical composition, and the way in which it is
The Grand Canyon, an incision through layers of sedimentary rocks.
A balancing rock called Kummakivi (literally "strange stone")
Rock outcrop along a mountain creek near OrosÃ, Costa Rica.
Sample of igneous gabbro
Diagenesis
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Diagenesis is the process of physical and chemical changes in sediments first caused by water-rock interactions, microbial activity, and compaction after their deposition. Increased pressure and tempe
A form of diagenesis is permineralization, in which buried organisms are replaced by minerals. These trilobites (Lloydolithus) were replaced by pyrite during a specific type of permineralization called pyritization.
Originally calcitic crinoid stem (in cross-section) diagenetically replaced by marcasite in a siderite concretion; Lower Carboniferous.