Jasper

Dyed blue to imitate lapis, "Swiss lapis": lack of pyrite inclusion, chelsea - greenish-blue to red - Blue Chart Gem Identification, Herve Nicolas Lazzarelli, 2010, p 7 6.5 to 7Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010) 2.58 to 2.91Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010) More from other references NoneWalter Schumann, Gemstones of the world (2001) Conchoidal,SplinteryWalter Schumann, Gemstones of the world (2001) 1.540 (+/-)Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010) More from other references Uniaxial/+Ulrich Henn and Claudio C. Milisenda, Gemmological Tables (2004) NoneWalter Schumann, Gemstones of the world (2001) More from other references AbsentWalter Schumann, Gemstones of the world (2001) NoneWalter Schumann, Gemstones of the world (2001) All colors, mostly striped or spotted.Walter Schumann, Gemstones of the world (2001) More from other references Orange to red, submicroscopic to microscopic inclusions of hydrous Fe oxidesW. William Hanneman, Pragmatic Spectroscopy For Gemologists (2011) OpaqueHerve Nicolas Lazzarelli, Blue Chart Gem Identification (2010) NoneWalter Schumann, Gemstones of the world (2001) TrigonalUlrich Henn and Claudio C. Milisenda, Gemmological Tables (2004) Microcrystalline aggregateWalter Schumann, Gemstones of the world (2001) Occurs as extensive beds of sedimentary or metamorphic origin. Jasper occurs as a cavity filling or as nodules or veins in iron ores. It occurs in altered igneous rocks and in detrital deposits. It may occur in variegated red to brown colours as a petrifying agent of wood.Michael O?Donoghue, Gems, Sixth Edition (2006) Jasper information at mindat.org Czech Republic  No reference listed Madagascar  mindat.org Morocco  mindat.org Netherlands  mindat.org Peru  Portugal  mindat.org Russia  Занимательная минералогия, Ферсман А., 1953, стр. 50 USA  Symons, Henry Heilbronner (1940), Quartz gem stones of California: Rocks & Minerals: 15: 41; Murdoch, Joseph & Robert W. Webb (1966), Minerals of California, Centennial Volume (1866-1966): California Division Mines & Geology Bulletin 189: 317. [var: Orbicular Jasper] Melhase, John (1934), A diversity of many fine minerals available in California for collectors: Oregon Mineralogist: 2(7): 7; Mineralogist, The (1935): 3(3): 34; Murdoch, Joseph & Robert W. Webb (1966), Minerals of California, Centennial Volume (1866-1966): California Division Mines & Geology Bulletin 189: 318; www.cst.cmich.edu/users/dietr1rv/jasper.htm U.S. Geological Survey, 2005, Mineral Resources Data System: U.S. Geological Survey, Reston, Virginia.