Crystallography Crystallography of Gold of Gold
A BeautifulAElement Beautiful InElement All Of It’sInCountless All Of It’s Forms Countless AndForms Shapes And Shapes
old is a unique substance old is a unique with substance extraordinary with properties. extraordinary An element, properties. a mineral An element, and aametal, mineral gold and occurs a metal, in nature gold occurs in alloyed commonly alloyed with commonly silver but also with with silver palladium, but also with mercury, palladium, and copper. mercury, Adding and copper. to it’s allure, Adding gold toisit’s one allure, of only gold is one nine elements that nineoccur elements in nature that in occur its native in nature or uncombined in its native or form. uncombined form.
Because it’s so soft, Because goldit’s can socollect soft, gold and can formcollect nuggets andinform fluvial nuggets beds and in fluvial even beds be absorbed and even bybe trees. absorbed Though bygold trees. Thoug nuggets as big nuggets as severalasfeet bigin asdiameter several feet have in been diameter discovered, have been single discovered, crystals are single quite crystals rare and aresmall. quite Native rare and gold small. Nati crystals usually crystals form skeletal usuallyrounded form skeletal octahedrons, roundedcubes, octahedrons, and dodecahedrons. cubes, and dodecahedrons. Sometimes theySometimes are elongated they in are elong specific crystallographic specific crystallographic directions forming directions herringbone forming or herringbone dendritic twins. or dendritic Others may twins. be Others flattened may with beoctahedral, flattened with oct cubic, or triangular cubic, faces. or triangular faces.
G O L D AT T H E GO MLODL E AC T UTLHAER ML O EV LEC L ULAR LEVEL Gold’s crystal Gold’s structure crystal is close-packed, structure is close-packed, face-centered cubic face-centered – imagine cubic an atom – imagine of gold an atom of gold at each corner of at aeach cubecorner and inofthe a cube middle andofin the middle of each face. Usingeach up 74% face. of Using the space, up 74% thisof isthe onespace, this is one of the most efficient of theways mostfor efficient spheresways to pack for spheres to pack together. Gold shares together. its Gold face-centered shares itscubic face-centered cubic crystal structurecrystal with copper, structure nickel, withplatinum, copper, nickel, platinum, and lead. and lead.
The crystallography, The crystallography, metallography, metallography, and composition and of composition gold directlyofinform gold directly its remarkable inform its remarkable properties – how properties it reacts –tohow pressure, it reacts temperature, to pressure,and temperature, fluids, and and evenfluids, its color. and Quantum even its color. Quantum chemistry tells us chemistry that gold’s tells electrons us that gold’s move so electrons rapidly move that they so rapidly shift the that wavelength they shift the of absorbed wavelength of absorbed light to blue andlight reflect to blue the opposite and reflect color: thelustrous opposite metallic color: lustrous yellow. metallic yellow. Gold’s other properties Gold’s other include properties resistance include to corrosion, resistance electrical to corrosion, conductivity, electrical and conductivity, malleability.and malleability. Gold is quite soft Gold – one is quite gramsoft of gold – onecan gram be flattened of gold can into bea flattened one-meter into square a one-meter sheet! It square keeps sheet! It keeps astronauts cool and astronauts protected coolfrom and the protected sun and from looks the fancy sun and on French looks fancy desserts. on French desserts.
Cubic crystals withinCu a
F U N F A C T S AFB UO NUFTAG CO TS L DA B O U T G O L D THE RAREST TYPE O TH F EG O RA LD R EI S ST. . . T Y P E O F G O L D I S . . .
Gold” “Wire Gold” FiliforM, “WireFiliforM, Largest known specimen: Largest known specimen:
The Ram’s Horn The Ram’s Horn WORLD’S LARGESTW S IONRGLLDE’ SC L RA YR ST GAELS.T. . S I N G L E C R Y S T A L . . .
217.78 G 217.78 G
Unearthed in Venezuela, the trapezohedron specimen is stored at Los Alamos National Laboratory in New Mexico.
Unearthed in Venezuela, the trapezohedron specimen is stored at Los Alamos National Laboratory in New Mexico.
G O L D H A S E X T R E MG E OMLA DL H L EAASBEI L X ITTRYE. .M . E M A L L E A B I L I TY. . .
1 Gram = 1 Meter1 Gram Square = 1sheet! Meter Square sheet! Large trapezohedronLarge crystal trapezohedron (Side A) crystal (Side A)
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