Gold Related Information

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Physical Properties of Gold

Lustre: Metallic
Diaphaneity (Transparency): Opaque
Colour: Rich yellow, paling to whitish-yellow
Streak: Shining yellow
Hardness (Mohs): 2½ - 3
Hardness (Vickers): VHN10=30 - 34 kg/mm2
Hardness Data: Measured
Tenacity: Malleable
Cleavage: None Observed
Fracture: Hackly
Density (measured): 15 - 19.3 g/cm3
Density (calculated): 19.309 g/cm3
Comment: Calculated density at 0° C.

Other Information

Fluorescence in UV light: none
Thermal Behaviour: Melting Point: 1062.4° ± 0.8°
Other Information: Completely soluble with Copper. Insoluble in acids except aqua regia, with incomplete separation if more than 20% of silver is present. Reported as spongy alteration pseudomorphs after Calaverite (Cripple Creek).
Health Warning: No information on health risks for this material has been entered into the database. You should always treat mineral specimens with care.
Industrial Uses: Electrical conductor, transparent reflective coating, jewelry, dentistry, coinage, decorative coatings Common Impurities: Ag,Cu,Pd


How do gold deposits form?

Gold has been prized throughout the history of mankind due to its appearance, ease of working and resistance to corrosion. Although jewellery remains the major use for gold, its unique chemical and physical properties mean that it has found many diverse applications in today's world: Gold nugget

* computer circuitry
* cosmic ray protection for spacecraft and satellites
* telephones, telescopes and photocopiers
* thermometers
* nightsights and security cameras
* lasers
* dentistry, eye surgery, treatment for arthritis
* aircraft engines and windows
* heat reflecting face visors
* Cancer treatments

So where does gold come from?

Deposits of gold can form in many geological environments: in deep magma chambers, in ancient volcanoes or hotsprings, or in conglomerates and sandstones that might form as a result of the weathering and erosion of these gold-bearing rocks.

However, one of the most common places that gold deposits form is in ancient fault zones, many of which were active during the earliest period of Earth's history, the Archaean (more than 2.5 billion years ago). Earthquakes produced by movements on these giant faults would have been accompanied by the release of hydrothermal solutions from deep in the Earth's crust. These solutions moved up along the faults and, often as a result of effervescence of carbon dioxide gas (rather like opening a bottle of fizzy drink), precipitated gold in economic concentrations in veins of quartz.

There are many types of gold deposits including epithermal vein deposits, intrusion-related breccia pipes, mesothermal turbidite- and greenstone-hosted deposits, contact deposits (skarns), replacement deposits, disseminated ores, placers, and Archean banded-iron formation deposits.

Gold Weights & Measures

  • % Gold

    European System:
    Gold present

    Karat System:
    Gold present


    1,000 parts fine

    24 karats


    917 parts fine

    22 karats


    750 parts fine

    18 karats


    585 parts fine

    14 karats


    500 parts fine

    12 karats


    416 parts fine

    10 karats

Note that the karat used above designates a degree of gold purity, and is not to be confused with the carat, equaling a fifth of a gram, which is used to state the weight of a gem stone.

The Weight of gold or gold articles is usually expressed in troy ounces. The Table below provides a convenient way of translation between troy ounces and other units of weight.

Fineness of Gold in Fraser River and some Tributary streams.

Fraser River Average


20.820 K

Coquihalla River


21.0 K

Thompson River


19.848 K

Bridge River


20.28 K

Watson Bar Creek


21.408 K

Poison Mnt. Creek


20.160 K

Quesnel River


19.92 K

Cariboo River


20.424 K

Cottonwood River


21.62 K

Willow River


21.43 K

Goat River


23.28 K



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