I - Indicies Color. { ______ ______. Sub Conchoidal - Fractures developed in brittle materials characterized by semi-curving surfaces. var printReadyElem = document.getElementById("printReady"); By signing up for this email, you are agreeing to news, offers, and information from Encyclopaedia Britannica. Aragonite, widespread mineral, the stable form of calcium carbonate (CaCO3) at high pressures. Aragonite has an orthorhombic structure and calcite a trigonal structure. The key difference between calcite and aragonite is that the crystal system of calcite is trigonal, whereas the crystal system of aragonite is orthorhombic. drag2 - RMB Resize/Rotate { printWin.document.open(); Let us know if you have suggestions to improve this article (requires login). drag1 - LMB Manipulate Structure Oxygen 47.96 % O. if (headTags.length > 0) alert("Sorry, the print ready feature is only available in modern browsers. _uacct = "UA-3067463-1"; Chemical Formula. Dbl Clk - Start-Stop Rotation S - Stereo It may be distinguished from calcite, the commoner form of calcium carbonate, by its greater hardness and specific gravity. Calcium carbonate, sometimes with some strontium, lead, and zinc. Warning: this large pop-up is very compute intensive and Both calcite and aragonite are two different forms of the same compound, i.e., calcium carbonate (CaCO 3). Aragonite Group. Dispersion weak, r < v. NAME( Duda&Rejl90) PHYS. Calcium 40.04 % Ca 56.03 % CaO. Black Friday Sale! { For detailed physical properties, see carbonate mineral (table). var headTags = document.getElementsByTagName("head"); Omissions? Mindat.org's Discussion Groups This article was most recently revised and updated by, https://www.britannica.com/science/aragonite, The Mineral and Gemstone Kingdom - Aragonite, Mineralogy Database - Aragonite Mineral Data, Amethyst Galleries - The Mineral Aragonite. } Our editors will review what you’ve submitted and determine whether to revise the article. printWin.document.write(html); Aragonite, widespread mineral, the stable form of calcium carbonate (CaCO3) at high pressures. Aragonite is meta-stable and about 1.5 times as soluble as calicte in seawater. Aragonite is the mineral normally found in pearls. Composition: Molecular Weight = 100.09 gm. Keyboard Calcite and aragonite are polymorphs meaning they have the same chemical formula, but different crystaline structures. PROP. Aragonite is an important element in the shells and tests of many marine invertebrates. var gAutoPrint = true; // Flag for whether or not to automatically call the print function } { if (gAutoPrint) Mineral Discussion Forum from Fabre Minerals - also available in RMB - Cycle Display Modes urchinTracker(); Print or Cut-and-Paste your Aragonite Specimen Label here : Español printWin.document.close(); Be on the lookout for your Britannica newsletter to get trusted stories delivered right to your inbox. var printWin = window.open("","printSpecial", 'toolbar=no,location=no,directories=no,status=no,menubar=no,scrollbars=yes,resizable=yes,copyhistory=yes,width=350,height=350'); Colorless, White, Gray, Yellowish white, Reddish white. Fluorescent and phosphorescent, Short UV=green,yellow white, Long UV=green, yellow pink. The Ca analogue of strontianite. { M - Menu I - Data Info Updates? S - Stereo Pair on/off The two different mineral species calcite and aragonite both possess the chemical formula CaCO 3. }, University of Colorado - Mineral Structure Data, a = 4.959, b = 7.968, c = 5.741, Z = 4; V = 226.85 Den(Calc)= 2.93. printWin.print(); Aragonite is always found in deposits formed at low temperatures near the surface of the Earth, as in caves as stalactites, in the oxidized zone of ore minerals (with lead substituting for calcium), in serpentine and other basic rocks, in sediments, and in iron-ore deposits. Aragonite and calcite have the same chemical formula, CaCO 3, but their atoms are stacked in different configurations. Drag2 - Resize F - Fit to Screen A - Atoms On/Off Scale: Size Not Given. function printSpecial() It is polymorphous (same chemical formula but different crystal structure) with calcite and vaterite, and, with geologic time, probably inverts to calcite even under normal conditions. Aragonite was named by Abrahan Gottlieb Werner after Molina de Aragón, Spain, the type locality where this mineral was first described. (Another example is the trio of kyanite, andalusite, and sillimanite.) Ask about Aragonite here : Help on Above. (Collectors Book of Fluorescent Minerals) OPTIC PROP. html += '\n\n'; - Start-Stop Rotation Although chemically identical, these two species are structurally very different; calcite crystalizes according to the rhombohedral crystal system while aragonite crystallizes according to the orthorhombic crystal system. CaCO3. Premium Membership is now 50% off! html += headTags[0].innerHTML; { Encyclopaedia Britannica's editors oversee subject areas in which they have extensive knowledge, whether from years of experience gained by working on that content or via study for an advanced degree.... …composed almost entirely of metastable aragonite (CaCO. (Ca, Sr, Pb, Zn )CO3. Variable Formula. Ask-A-Mineralogist from the Mineralogical Society of America (Heinrich65). Composition. "); P - Polyhedra On/Off } html += '\n\n\n'; return; The principal member of the Aragonite Group, aragonite is the second most common polymorph of natural calcium carbonate (the most common is calcite).It is significantly less widespread and abundant than calcite and is formed under a much narrower range of physiochemical conditions. else if (document.getElementsByTagName != null) Location: Tsumeb mine, Tsumeb, Namibia. Original Rockhounds Discussion Group Comments: Clear, crystalline aragonite prism. It may be distinguished from calcite, the commoner form of calcium carbonate, by its greater hardness and specific gravity. Carbon 12.00 % C 43.97 % CO 2. Aragonite is always found in deposits formed at low temperatures near the if (printReadyElem != null) else General Aragonite Information. Mouse var html = '\n\n'; Help on Above, de Villiers J P R , American Mineralogist , 56 (1971) p.758-767, Crystal structures of aragonite, strontianite, and witherite. B - Bonds On/Off html += printReadyElem.innerHTML; Pseudo Hexagonal - Crystals show a hexagonal outline. if (document.getElementById != null) Its empirical formula is Na Al 2 [ (O H) 2 |Al Si 3 O 10 ].