Geographic Minerals

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

Definition – Dryhead Agate is one of the most beautiful agates found anywhere. It is found in southern Montana between the Big Horn and Pryor…

Definition – Goshenite is the purest form of Beryl mineral, which is colorless, free from any kind of impurities. In most cases, color in beryl…

Definition – Euclase is a beryllium aluminium hydroxide silicate mineral (BeAlSiO4(OH)), that crystallizes in the monoclinic system and is typically massive to fibrous as well…

The mineral marcasite sometimes called “white iron pyrite”, is iron sulfide (FeS2) with an orthorhombic crystal structure. It is a yellow to silvery-yellow iron sulfide…

Definition – Anhydrite, or anhydrous calcium sulfate, is an evaporite mineral with the chemical formula CaSO4, that occurs in extensive layered deposits in sedimentary basins…

Definition – Scapolite (Gr. σκάπος, rod, and λίθος, stone) any of a group of feldspathoid minerals found in calcium-rich metamorphic rocks, particularly marble, gneiss, granulite,…

Definition – Rose Quartz, translucent, usually turbid, very coarse-grained variety of the silica mineral quartz found in pegmatites. It is the name used for pink…

Definition – Smoky Quartz is a color-variety of crystalline quartz. It is a grey, translucent variety of quartz that ranges in clarity from almost complete…

Manganvesuvianite is a tetragonal-dipyramidal deep maroon red mineral containing aluminum, calcium, hydrogen, iron, magnesium, manganese, oxygen, and silicon. It is a rare mineral with formula…

Definition – Helenite, also known as Mount St. Helens obsidian, emerald obsidianite, and ruby obsidianite, is a trade name used for a man-made glass that…

Definition – Fire Agate is a semi-precious stone that hails from the Quartz family. It is a rare and interesting gem of unusual beauty. It…