PROPERTIES OF GOLD

Out of the earth comes a remarkable metal with an unparalleled combination of chemical and physical properties that make this metal invaluable to a wide range of everyday applications essential to our modern life. Thousands of common, everyday appliances require gold to ensure perfect performance over a long period of time. This indestructible metal is completely recyclable and virtually immune to the effects of air, water, and oxygen. Gold will not tarnish, rust, or corrode. This unique combination of properties makes gold a vital component in many medical, industrial, and electrical applications. These properties include:

  • RESISTANCE TO CORROSION
  • ELECTRICAL CONDUCTIVITY
  • DUCTILITY AND MALLEABILITY
  • INFRARED (HEAT) REFLECTIVITY
  • THERMAL CONDUCTIVITY
    •

    RESISTANCE TO CORROSION

    Gold is the most non-reactive of all metals. It is benign in all natural and industrial environments. Gold never reacts with oxygen (one of the most active elements), which means it will not rust or tarnish. The gold death-mask in the tomb of Tutankhamun looked as brilliant when it was unearthed in 1922 as when it was entombed in 1352 BC.

    ELECTRICAL CONDUCTIVITY

    Gold is among the most electrically conductive of all metals. Since electricity is essentially the flow of charged particles in a current, metals that are conductive allow this current to flow unimpeded. Gold is able to convey even a tiny electrical current in temperatures varying from -55° to +200° centigrade. This makes gold a vital component for electrical connectors in computers and telecommunications equipment.

    DUCTILITY & MALLEABILITY

    Gold is the most ductile of all metals, allowing it to be drawn out into tiny wires or threads without breaking. As a result, a 1.02 ounce of gold can be drawn into a wire 100 km (62 miles) long. Gold's malleability is also unparalleled. It can be shaped or extended into extraordinarily thin sheets. For example, one ounce of gold can be hammered into a 100 square-foot sheet.

    INFRARED (HEAT) REFLECTIVITY

    Gold is the most reflective and least absorptive material of infrared (or heat) energy. High purity gold reflects up to 99% of infrared rays. This makes gold ideal for heat and radiation reflection, as in life-saving face shields for astronauts and firefighters.

    THERMAL CONDUCTIVITY

    Gold is an excellent conductor of thermal energy or heat. Since many electronic processes create heat, gold is necessary to transfer heat away from delicate instruments. Gold alloy is the most tenacious and long-performing material available for protection at high temperatures.
    For example: A 35% gold alloy is used in the main engine nozzle of the Space Shuttle, where temperatures can reach 3300° centigrade.
    HOW GOLD IS MEASURED (AND SOLD)
  • 3.086 grains = 1 carat
  • 24 grains = 1 pennyweight
  • 20 penneyweights = 1 ounce
  • 12 ounces = 1 pound

    • TECHNICAL DATA

    Gold: soft, dense, bright yellow metallic element. One of the transition elements.
    Symbol: Au (from Latin aurum, "gold")
    Periodic table: Atomic number: '79'. A transition element.
    Properties:
  • Hardness: (2.5 to 3)
  • Melting Point: About 1947 F (1064 C)
  • Boiling Point: About 2808 F (5086 C)
  • Specific Gravity: 19.3
  • Atomic Weight: 196.967

    • Miscellaneous:
  • Pure gold is the most malleable and ductile of all the metals.
  • It can be flattened to a thickness of 0.000005 in. (0.000013 cm).
  • 1.02 oz (29g) can be drawn into a wire 62 miles (100 km) long.
  • One of the softest metals. (hardness 2.5 to 3)
  • A good conductor of heat and electricity.
  • Pure Gold is bright yellow and has a high luster.
  • Finely divided gold, (like other metallic powders), is black.
  • Colloidal suspended gold ranges in color from ruby red to purple.
  • Is extremely inactive.
  • Is unaffected by air, heat, moisture, and most solvents.
  • Will dissolve in mixtures containing chlorides, bromides & some iodides.
  • Will also dissolve in many oxidizing mixtures, alkali cyanides and aqua regia;
        (a mixture of hydrochloric and nitric acids).
  • Chlorides and cyanides are important compounds of gold.
  • Gold occurs in seawater 5 to 250 parts (by weight) to 100 million parts of
        water. Gold present in seawater is more than 9 billion metric tons.
        Cost of recovering would be far greater than the value of the gold.