One of the most unreactive metals in the periodic table of elements. Alchemists used to call gold one of the "noble" metals because of its resistance to oxidation under most normal circumstances. Its chemical symbol is Au, short for Aurum, which is Latin for gold.
Gold has many varied uses which range from ornaments to jewellery to electronics to spacecraft to medicine.
Physical characteristics Gold is relatively soft -- pure gold is indentable by the pressure of human teeth.
It is also the most malleable and ductile of all metals -- one ounce of pure gold can be pounded into a thin sheet of metal measuring 300 square feet and can be drawn into a thin wire 5 miles long.
Gold is the most reflective and least absorptive material of infrared (heat) energy -- high purity gold reflects up to 99% of infrared rays. Gold is also an excellent conductor of thermal energy or heat -- a 35% gold alloy is used in the main engine nozzle of the Space Shuttle, where temperatures can reach 3300° centigrade.
The specific gravity or density of pure gold is 19.3 compared to 14.0 for mercury and 11.4 for lead.
Gold mining Gold is scarce and occurs naturally as impure gold, with a density of between 16 to 18. The rock that gold is commonly found in has a density of about 2 to 3. The difference in density enables gold to be separated from clay, silt, sand, and gravel by agitating with devices such as the gold pan (panning for gold), rocker, and sluicebox.
Gold is often recovered from ore by reacting with mercury which forms an amalgam with gold. Gold is extracted from the amalgam by heating the amalgam to remove the mercury. Cyanide is sometimes used for extracting gold from low grade ores.
Karats and purity Not to be confused with carats (a measure of the weight of precious stones), a Karat (K) is a measure of the fineness or purity of gold expressed as a fraction of 24. Pure gold is thus 24K. Gold used in jewellery ranges from 9K to 22K. Pure gold tends not to be used very much in jewellery because it is too soft. Asians tend to prefer the higher Karat golds because they seem to value the intrinsic value of it more whereas 9K gold, which is relatively unpopular in Asian countries, is commonly found in jewellery in Western countries.
Gold medals are used to denote the winner in sports events such as the Olympics. A gold credit card shows a certain level of spending.
It has been estimated that ALL the gold ever mined throughout human history up to today only amounts to about 150,000 tons. Did you know all this would, if melted together, only make one solid cube about 30m on each side? Yes, it is that rare.
Once regarded as money, gold has been relegated to the level of a "barbarous relic" and the price of gold has been in a downward bear market for about 20 years since the spike to US$800/ounce in 1980 until the action got interesting recently...
Goldbugs can catch in on the commentary everyday at the Gold Discussion Forum at kitco.com at http://www.kitcomm.com/cgi-bin/comments/gold/display_short.cgi
Some figures: Symbol - Au Atomic Number - 79 Atomic Weight - 196.96655 Melting Point - 1064.43°C (1337.5801 K, 1947.9741°F) Boiling Point - 2807.0°C (3080.15 K, 5084.6°F) Specific Gravity - 19.32
Yellow gold: Traditional. Silver, copper and zinc.
White gold: Copper and silver with extra zinc, nickel, and/or palladium for the white color. Palladium is most likely used as only a thin plating.
Green Gold: Silver, copper, and zinc, but with extra silver to make it greenish. (Some times uses only silver)
Pink gold: Silver, copper, and zinc, with extra copper.
Gold purity is measured in carats. One carat is one twenty-fourth part, Fine gold is 24 carat (also karat, ct. or k.). Therefore only yellow gold can be 24 k. (100% gold).
http://hooverandstrong.com/products/millprod/casting.htm Is a good site to see the different colors of gold.
"Sorry," the angel said, "but you can't take your wealth with you." The man implored the angel to speak to God to see if He might bend the rules. The man continued to pray that his wealth could follow him.
The angel reappeared and informed the man that God had decided to allow him to take one suitcase with him. Overjoyed, the man got his largest suitcase, filled it with pure gold bars and placed it beside his bed. Soon afterward the man died and showed up at the gates of heaven to greet St. Peter.
St. Peter, seeing the suitcase, said, "Hold on, you can't bring that in here!" The man explained to St. Peter that he had permission and told him to verify his story with God.
St. Peter checked and came back saying, "You're right. You are allowed one carry-on bag, but I'm supposed to check its contents before letting it through." He opened the suitcase to inspect the worldly items that the man found too precious to leave behind and exclaimed, "You brought pavement?"
source:alt.quotations
Symbol: Au Atomic number: 79 Atomic weight: 196.96655 Density (at room temperature and pressure): 19.3 g/cc Melting point: 937.4°C Boiling point: 1,064°C Valence: +1, +3 Ground state electron configuration: [Xe]4f145d106s1
ASCII Art Representation: ,%%,, ,%%%%%%, ,%%%%%%%, ,%%%%%%"%%%, ,%%%%%" "%%%, %%%%%" "%%%%, ,%%%%" "%%%%%,, ,%%%%" "%%%%%%%,,, ,%%%%" ,%%, "%%%%%%%%%%%%% ,%%%"" "%%%%%%%%%%%%%%%%%%% "%%%%%%%%% ,%%%"" %%%% """%%% ,,%""" %%%% %%%% %%%% ,%%, "%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %%%% ,, %%%% , "%%,, %%%% ,%%%,, %%%%, %%%% ,%%%%%%" %%%%%, %%%% ,%%%%" %%%%% %%%% ,%%%" """ %%%% ,%%" ,%%, "%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% Character Etymology: Once written with four dots along the base, like ::, instead of the present two ..; they represent nuggets buried in the ground. There is a range of oppinions regarding the topmost stroke, but it should be taken generally as a covering or mound of earth representing the concealment of something valuable. The word for covering shares phonetic simularity with the word for shine, making the topmost stroke representation of covering more likely. A Listing of All On-Yomi and Kun-Yomi Readings: on-yomi: KIN KON GON kun-yomi: kane kana- -gane kan kimu ko kono n Nanori Readings: Nanori: kan kimu ko kono n English Definitions: KON, GON, KIN: gold, money; Friday. kane: money, metal. kana-: metal Unicode Encoded Version: 金 Unicode Encoded Compound Examples: 金杯 (kimpai): gold cup. 金魚 (kingyo): goldfish. 金曜日 (kinyoobi): Friday. 金権 (kinken): the almighty dollar, financial influence.
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Once written with four dots along the base, like ::, instead of the present two ..; they represent nuggets buried in the ground. There is a range of oppinions regarding the topmost stroke, but it should be taken generally as a covering or mound of earth representing the concealment of something valuable. The word for covering shares phonetic simularity with the word for shine, making the topmost stroke representation of covering more likely.
on-yomi: KIN KON GON kun-yomi: kane kana- -gane kan kimu ko kono n
Nanori: kan kimu ko kono n
金
金杯 (kimpai): gold cup. 金魚 (kingyo): goldfish. 金曜日 (kinyoobi): Friday. 金権 (kinken): the almighty dollar, financial influence.
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The 'goldy' colour of gold actually has an interesting origin... The colour of anything depends on how the photons of light interact with the electrons in the material. Take silver it's 'colour' originates from an electron absorbing an ultra-violet photon; eveything else is reflected, giving the silvery white appearance. Now the electronic configuration of gold is similar to that of silver, and to a first approximation calculations show that gold too should have a 'silver' appearance.
The reason why it doesn't lies with relativity. The electrons which orbit the atomic nucleus must have enough energy to not fall into the nucleus, for hydrogen this corresponds to a speed of about 2 × 106 metres per second. (Please read the electron orbitals node for a grounding on this topic. As you go up the periodic table, the attraction between the (ever larger) nucleus and the electron increases. The electron has to have more energy, or it will fall into the nucleus. By the time you've got to gold (atomic number 79, or 79 protons), the electron nearest the nucleus (1s) have a speed of 1.6 8 metres per second. This is about half the speed of light, and now relativistic effects have to be taken into account....
Special relativity shows us that mass depends on speed (check the relativity node for the equations), and with gold this means it's electrons are 1.2 times heavier than they would be at rest. Now the distance the electrons orbit the nucleus depends on their mass; the greater the mass, the smaller the orbit. If you ignore relativity gold should be about 290 pico metres in diameter, but it is actually closer to the relativity predicted value of 244 pm. (Which is in fact smaller than the silver atom!) The electrons in the s and p orbitals actually spend most of their time near the nucleus, and so they are heavily influenced by this effect, the electrons in 'higher' orbitals d,f don't spend time near the nucleus and so are less affected. This in turn means that now the (negatively charged) s and p electrons are much closer to the (positive) nucleus, they increase the shielding of the higher orbitals from the attraction of the nucleus, which destabilises these higher orbitals, and they balloon outwards, losing energy.
Now the ultra-violet absorbtion in silver described above takes place between the 5s and 4d orbitals, and a similar transistion between 6s and 5d in gold gives it it's colour. In gold the relativistic effects have decreased the gap between these levels, and the frequency of light absorbed is similary decreased and is now in the visible range. Which is why gold has a colour, and it's yellow!
Non-rel Rel Non-Rel Rel Orbital -5_ energies | _____ (eV) | \_____ _____ | 5s \_____ | 6s -10| | | 5d _____ | 4d _____ _____/ | ______/ -15| Silver Gold
Ryan Adams - Gold
Track Listing:
Initial copies of Gold came with a 5-track EP called Side Four; its track listing was:
Personnel:
