Geographic Minerals

Definition – Analcime, also called analcite (from the Greek analkimos – “weak”), common feldspathoid mineral, a hydrated sodium aluminosilicate (NaAlSi2O6·H2O) that occurs in seams and…

Definition – Novaculite, also called Arkansas Stone, ivery dense, light-coloured, even-textured sedimentary rock, a bedded chert in which microcrystalline silica (silicon dioxide, SiO2) in the…

Definition – Mariposite is beneficial and strong stone; it is a mineral which is a chromium-rich variety of mica, which imparts an attractive green color…

Definition – Flint is a sedimentary cryptocrystalline form of the mineral quartz, categorized as the variety of chert that occurs in chalk or marly limestone.…

Definition – Breccia (/ˈbrɛtʃiə/ or /ˈbrɛʃiə/) lithified sedimentary rock consisting of angular or subangular fragments larger than 2 millimeters (0.08 inch). It differs from a…

Definition – Gneiss (/ˈnaɪs/) is a globally common type of metamorphic rock that can easily be identified by its alternating layers of minerals known as…

Definition – Caliche (/kəˈliːtʃiː/) is a shallow layer of soil or sediment in which the particles have been cemented together by the precipitation of mineral…

Definition – Obsidian is an igneous rock occurring as a natural glass formed by the rapid cooling of viscous lava from volcanoes. It is produced…

Definition – Gabbro (/ˈɡæbroʊ/) is a phaneritic (coarse-grained), is an intrusive igneous rock that forms from the result of slow cooling of magma inside of…

Margaritasite is a yellow, cesium-bearing mineral in the carnotite group. Its chemical formula is (Cs, K, H3O)2(UO2)2V2O8·H2O and its crystal system is monoclinic. It was…

Definition – Hornfels is a fine-grained metamorphic rock that was formed by the contact between mudstone/shale, or other clay-rich rock, and a hot igneous body,…

Definition – Chert (/ˈtʃɜːrt/) is a sedimentary rock composed of microcrystalline or cryptocrystalline quartz, the mineral form of silicon dioxide (SiO2). It occurs as nodules,…