Alunite, or alumstone, is a mineral that was first observed in the 15th century at Tolfa, near Rome, where it was mined for the manufacture of alum. First called aluminilite by JC Delametherie in 1707, this name was contracted by FS Beudant in 1824 to alunite. This article is about minerals in the geologic sense; for nutrient minerals see dietary mineral; for the band see Mineral (band). ... (14th century - 15th century - 16th century - other centuries) As a means of recording the passage of time, the 15th century was that century which lasted from 1401 to 1500. ... City motto: Senatus Populusque Romanus – SPQR (The Senate and the People of Rome) Founded 21 April 753 BC mythical, 1st millennium BC Region Latium Mayor Walter Veltroni (Democratici di Sinistra) Area  - City Proper  1290 km² Population  - City (2004)  - Metropolitan  - Density (city proper) 2,546,807 almost 4,000,000 1... For alum meaning graduate, see Alumn. ... François Sulpice Beudant (September 5, 1787 - December 10, 1850), French mineralogist and geologist, was born in Paris. ...

Distinct crystals of alunite are rarely found in cavities in the massive material. Alunite crystallizes in the hexagonal system with crystals forming trigonal pyramids that resemble rhombohedra with interfacial angles of 90 50', so that they resemble cubes in appearance. Minute glistening crystals have also been found loose in cavities in altered rhyolite. Alunite varies in color from white to yellow gray. The hardness is 4 and the specific gravity is between 2.6 and 2.8. The mineral is a hydrated aluminium potassium sulfate, KAl₃(SO₄)₂(OH)₆. Sodium substitutes for potassium and when high in sodium it is called natroalunite. It is insoluble in water or weak acids, but soluble in sulfuric acid. Jarosite is an iron analogue in which Fe³⁺ replaces the aluminium. It occurs as a secondary mineral on iron sulfate ores. Quartz crystal A crystal is a solid in which the constituent atoms, molecules, or ions are packed in a regularly ordered, repeating pattern extending in all three spatial dimensions. ... A regular hexagon A hexagon (also known as sexagon) is a polygon with six edges and six vertices. ... In crystallography, the rhombohedral (or trigonal) crystal system is one of the 7 lattice point groups. ... Rhyolite Rhyolite is an igneous, volcanic (extrusive) rock, of felsic composition, with aphanitic to porphyritic texture. ... In materials science, hardness is the characteristic of a solid material expressing its resistance to permanent deformation. ... Relative density (also known as specific gravity) is a measure of the density of a material. ... General Name, Symbol, Number aluminium, Al, 13 Chemical series poor metals Group, Period, Block 13, 3, p Appearance silvery Atomic mass 26. ... General Name, Symbol, Number potassium, K, 19 Chemical series alkali metals Group, Period, Block 1, 4, s Appearance silvery white Atomic mass 39. ... Sulfate is the IUPAC name for the SO42- ion, consisting of a central sulfur atom single bonded to four tetrahedrally oriented oxygen atoms. ... Sulfuric acid (British English: sulphuric acid), H2SO4, is a strong mineral acid. ... Jarosite is a basic hydrous sulfate of potassium and iron with a chemical formula of KFe3(OH)6(SO4)2. ...

Alunite occurs as veins and replacement masses in trachyte, rhyolite, and similar potassium rich volcanic rocks It is formed by the action of sulfuric acid bearing solutions on these rocks during the oxidation and leaching of metal sulfide deposits. Alunite also is found near volcanic fumaroles. The white, finely granular masses closely resemble finely granular limestone, dolomite, anhydrite, and magnesite in appearance. The more compact kinds from Hungary are so hard and tough that they have been used for millstones. Trachyte is an igneous, volcanic (extrusive) rock, with aphanitic to porphyritic texture. ... Rhyolite Rhyolite is an igneous, volcanic (extrusive) rock, of felsic composition, with aphanitic to porphyritic texture. ... Volcanic rock on North America Plutonic rock on North America Igneous rocks are formed when molten rock (magma) cools and solidifies, with or without crystallization, either below the surface as intrusive (plutonic) rocks or on the surface as extrusive (volcanic) rocks. ... Sulfuric acid (British English: sulphuric acid), H2SO4, is a strong mineral acid. ... The most fundamental reactions in chemistry are the redox processes. ... Sulfur deposits near a fumarole A fumarole (Latin fumus, smoke) is an opening in Earths (or any other astronomical bodys) crust, often in the neighborhood of volcanoes, which emit steam and gases such as carbon dioxide, sulfur dioxide, hydrochloric acid, and hydrogen sulfide. ... Limey shale overlaid by limestone. ... Dolomite from Touissite, Morocco Dolomite is a mineral (formula CaMg(CO3)2) consisting of a calcium magnesium carbonate found in crystals and in beds as dolostone. ... Anhydrite is a mineral - anhydrous calcium sulfate, CaSO4. ... Magnesite is magnesium carbonate, MgCO3. ...

Historically extensive deposits were mined in Tuscany and Hungary, and at Bulladelah in New South Wales. Currently found at Tolfa, Italy. In the U. S. A. it is found in the San Juan district of Colorado; Goldfield, Nevada; Marysvale, Utah; and Red Mountain in the Patagonia district of Arizona. The Arizona occurrence lies appropriately above a canyon named Alum Gulch. Alunite is mined as an ore of both potassium and aluminium at Marysvale. Some of the ore deposits were located by airborne and satellite multispectral imaging. Tuscany (Italian Toscana) is a region in central Italy, bordering on Latium to the south, Umbria to the east, Emilia-Romagna and Liguria to the north, and the Tyrrhenian Sea to the west. ... Motto: Orta Recens Quam Pura Nites (Newly Risen, How Brightly You Shine) Nickname: First State, Premier State Other Australian states and territories Capital Sydney Government Governor Premier Const. ... This is the article on the state. ... State nickname: Silver State, Battle Born State (official) Other U.S. States Capital Carson City Largest city Las Vegas Governor Kenny Guinn (R) Official languages None Area 286,367 km² (7th)  - Land 284,396 km²  - Water 1,971 km² (0. ... State nickname: Beehive State Other U.S. States Capital Salt Lake City Largest city Salt Lake City Governor Jon M. Huntsman, Jr. ... State nickname: The Grand Canyon State, The Copper State Other U.S. States Capital Phoenix Largest city Phoenix Governor Janet Napolitano (D) Official languages English Only State Area 295,254 km² (6th)  - Land 294,312 km²  - Water 942 km² (0. ... An ore is a mineral deposit containing a metal or other valuable resource in economically viable concentrations. ...

References

• Hurlbut, Cornelius S., 1966 pr, Dana's Manual of Mineralogy, 17th ed., ISBN 0471032883
• Hurlbut, Cornelius S.; Klein, Cornelis, 1985, Manual of Mineralogy, 20th ed., ISBN 0471805807
• Mineral Galleries
• Webmineral