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Crystal. Crystals of amethyst quartz. Microscopically, a single crystal has atoms in a near-perfect periodic arrangement; a polycrystal is composed of many microscopic crystals (called "crystallites" or "grains"); and an amorphous solid (such as glass) has no periodic arrangement even microscopically. A crystal or crystalline solid is a solid ...
Aquamarine variety of beryl with tourmaline on orthoclase. Arsenopyrite from Hidalgo del Parral, Chihuahua, Mexico. Aurichalcite needles spraying out within a protected pocket lined by bladed calcite crystals. Austinite from the Ojuela Mine, Mapimí, Durango, Mexico. Ametrine containing amethyst and citrine, from Bolivia.
Agardite is a mineral group consisting of agardite-(Y), [4] [5] agardite-(Ce), [6] agardite-(Nd), [7] and agardite-(La). [8] They comprise a group of minerals that are hydrous hydrated arsenates of rare-earth elements (REE) and copper, with the general chemical formula (REE,Ca)Cu 6 (AsO 4) 3 (OH) 6 ·3H 2 O. Yttrium, cerium, neodymium, lanthanum, as well as trace to minor amounts of other REEs ...
A silicate mineral is generally an inorganic compound consisting of subunits with the formula [SiO 2+n] 2n−. Although depicted as such, the description of silicates as anions is a simplification. Balancing the charges of the silicate anions are metal cations, M x+. Typical cations are Mg 2+, Fe 2+, and Na +.
Enjoy a classic game of Hearts and watch out for the Queen of Spades!
Diatomite rock sample from Sisquoc Formation Scanning electron micrograph of diatomaceous earth. Diatomaceous earth (/ ˌ d aɪ. ə t ə ˈ m eɪ ʃ ə s / DY-ə-tə-MAY-shəs), diatomite (/ d aɪ ˈ æ t ə m aɪ t / dy-AT-ə-myte), celite or kieselgur/kieselguhr is a naturally occurring, soft, siliceous sedimentary rock that can be crumbled into a fine white to off-white powder.
Mineral. Crystals of serandite, natrolite, analcime, and aegirine from Mont Saint-Hilaire, Quebec, Canada. In geology and mineralogy, a mineral or mineral species is, broadly speaking, a solid substance with a fairly well-defined chemical composition and a specific crystal structure that occurs naturally in pure form. [1][2] The geological ...
Liquid crystal (LC) is a state of matter whose properties are between those of conventional liquids and those of solid crystals. For example, a liquid crystal can flow like a liquid, but its molecules may be oriented in a common direction as in a solid. There are many types of LC phases, which can be distinguished by their optical properties ...