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Native Silver. 5 cm. By Connor Jones. 7.4 cm. http://www.themineralgallery.com/silver.htm. Silver – Comes from Old English ‘ seolfor ’ and Ag from the Latin word Argentum. Native – Can be found singular or as an alloy in nature. Discovered around 6000 years ago . Native Silver.
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Native Silver 5 cm By Connor Jones 7.4 cm http://www.themineralgallery.com/silver.htm
Silver – Comes from Old English ‘seolfor’ and Ag from the Latin word Argentum. • Native – Can be found singular or as an alloy in nature. • Discovered around 6000 years ago Native Silver
Chemical formula: Ag • Atomic mass: 47 • One electron in its outer shell • Commonly formed with small traces of gold, mercury, arsenic and antimony. • Common silver ores: • Argentiferous galena • Argentite – Ag₂S • Chlorargyrite – AgCl Chemistry of Silver
Isometric crystal system Face Centred Cubic Crystal Structure The sides are of the same length and are perpendicular to one another. Atomic packing factor of 0.74 Atoms (dots on diagram) are positioned on the face of the cube. http://en.wikipedia.org/wiki/File:Lattice_face_centered_cubic.svg
Crystal class – Hexoctahedral Crystal Structure http://webmineral.com/crystal/Isometric-Hexoctahedral.shtml http://webmineral.com/crystall.shtml
Silver In Nature Forming as cubic, octahedral and dodecahedral crystals but they are very rare! Wiry 3.1 cm Dendritic http://www.themineralgallery.com/silver.htm 10.2 cm 2.6 cm Massive 12 cm http://www.minfind.com/mineral-81498.html 5.1 cm http://www.themineralgallery.com/silver.htm 11 cm
Physical Properties Streak– Silvery white Hardness – 2.5 – 3 on the mohs scale Density – 10.5 g/cm³ Cleavage – None Fracturing – Hackly Other – Ductile, malleable and tarnishes in air. Silver has the highest electrical conductivity of any element and the highest thermal conductivity of any metal.
Optical Properties Reflectivity Colour in reflected light – Brilliant silver white Silver is not pleochroic 86.5% 69.8% Reflectance (%) Wavelength (nm) http://www.mindat.org/ograph.php?id=3664
Mineral Stability Silver is stable in pure air and water, but tarnishes when it comes into contact with ozone or hydrogen sulfide. Primarily found in hydrothermal veins and is soluble in any oxidising mineral acid. Formed at temperatures ~700 Kelvin and pressures ~5000 Bar total pressure. It is stable at ground level and doesn’t change its assemblage below 800 Kelvin
Where is Silver Formed? 3 Main Occurrences: Hydrothermal veins, secondary enrichment and alluvial nuggets. Silver is usually contained in sulfide ore veins. Mexico, Norway and Germany have large deposits of silver. The Himmelsfürt mine, Germany, contained dendritic and wiry crystals in abundance. Silver is a by product of many copper, gold, nickel and zinc refining.
Uses Technology Jewellery and Silverware Medicine Photography Monetary Optics and Mirrors
Conclusion On native silver and silver as an element • Geologically it is not of great importance • However it is: • Fundamental to our lifestyle and always has been • Rare, and therefore ‘precious’ • Produces some stunning mineral formations
References http://www.minerals.net/mineral/silver.aspx http://link.springer.com/article/10.1134%2FS1028334X06080162?LI=true# http://www.mindat.org/min-3664.html http://webmineral.com/data/Silver.shtml http://environmentalchemistry.com/yogi/periodic/Ag.html#Names