Afghanite, (Na,Ca,K)₈(Si,Al)₁₂O₂₄(SO₄,Cl,CO₃)₃·H₂O, is a hydrous sodium, calcium, potassium, sulfate, chloride, carbonate alumno-silicate mineral. Afghanite is a feldspathoid of the cancrinite group and typically occurs with sodalite group minerals. It forms blue to colorless, typically massive crystals in the hexagonal crystal system. It has a Mohs hardness of 5.5 to 6 and a specific gravity of 2.55 to 2.65. It has refractive index values of nω=1.523 and nε=1.529. It has one direction of perfect cleavage and exhibits conchoidal fracture. It fluoresces a bright orange. Hydrates are compounds formed by the union of water with some other substance, generally forming a neutral body, as certain crystallized salts. ... General Name, Symbol, Number sodium, Na, 11 Chemical series alkali metals Group, Period, Block 1, 3, s Appearance silvery white Atomic mass 22. ... General Name, Symbol, Number calcium, Ca, 20 Chemical series alkaline earth metals Group, Period, Block 2, 4, s Appearance silvery white Atomic mass 40. ... General Name, Symbol, Number potassium, K, 19 Chemical series alkali metals Group, Period, Block 1, 4, s Appearance silvery white Atomic mass 39. ... In inorganic chemistry, a sulfate (IUPAC-recommended spelling; also sulphate in British English) is a salt of sulfuric acid. ... The chloride ion is formed when the element chlorine picks up one electron to form an anion (negatively-charged ion) Cl−. The salts of hydrochloric acid HCl contain chloride ions and are also called chlorides. ... In inorganic chemistry, a carbonate is a salt of carbonic acid. ... The silicate minerals make up the largest and most important class of rock-forming minerals. ... Minerals are natural compounds formed through geological processes. ... The feldspathoids are a group of tectosilicate minerals which resemble feldspars but have a different structure and much lower silica content. ... Cancrinite is a mineral, a complex carbonate and silicate of sodium, calcium and aluminium; formula Na6Ca2[(CO3,Al6Si6O24].2H2O. Found originally in 1839 in the Ural Mountains, it is named after Count Kankrin, a Russian minister of finance. ... Sodalite is a rare, rich royal blue mineral widely enjoyed as an ornamental stone. ... In crystallography, the hexagonal crystal system is one of the 7 lattice point groups. ... Mohs scale of mineral hardness characterizes the scratch resistance of various minerals through the ability of a harder material to scratch a softer material. ... Relative density (also known as specific gravity) is a measure of the density of a material. ... The refractive index (or index of refraction) of a material is the factor by which the phase velocity of electromagnetic radiation is slowed in that material, relative to its velocity in a vacuum. ...

It was discovered in 1968 in the Lapis-lazuli Mine, Sar-e-Sang, Badakhshan Province, Afghanistan and takes its name from that country. It has also been described from localities in Germany, Italy, the Pamir Mountains, Tajikistan, near Lake Baikal in Siberia, New York and Newfoundland. It occurs as veinlets in lazurite crystals in the Afghan location and in altered limestone xenoliths within pumice in Pitigliano, Tuscany, Italy. A photograph of Ismail Samani Peak (then known as Peak Communism) taken in 1989. ... The references in this article would be clearer with a different and/or consistent style of citation, footnoting or external linking. ... Siberian Federal District (darker red) and the broadest definition of Siberia (red) Udachnaya pipe Siberia (Russian: , Sibir; Tatar: ) is a vast region of Russia constituting almost all of Northern Asia. ... A block of lapis lazuli Lapis lazuli is one of the oldest of all gems, with a history of use stretching back 7,000 years. ... Limey shale overlaid by limestone. ... The xenolith (Greek: foreign rock) is a rock which becomes enveloped in a larger rock during the latters development and hardening. ... Specimen of highly porous pumice from Teide volcano on Tenerife, Canary Islands. ...

References

• Mineral Data Publishing 2001
• Mindat with location data
• Webmineral data