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Ohaus Scales

All Ohaus scales listed here, except the LS-200, have the following features:

  • Refined load cell technology
  • Push button calibration
  • AC/DC powered
  • Tare function
  • LCD display
  • Auto Shutoff function
  • Low battery indicator
  • Calibration weight (except the LS-200, CT 600L & CT 1200)
  • Gold scoop
  • Removable weighing platform
  • Made in USA
  • 5 year warrantee
  • AC adapter


AV612N Legal Scale

AV612N Legal Scale

Meets legal requirements for weighing metal bought and sold. Weighs in grams, pennyweights, ounces & troy ounces. Max capacity 610 grams at .1 gram precision.  Learn more ›

$687.00

SKU: 9836


What is Specific Gravity?

Specific gravity is the weight in grams of one cubic centimeter of a metal.

 

The Specific Gravity Test is used to calculate the gold content of gold nuggets that contain a mixture of gold and other materials. In this example of the specific gravity test, we use gold mixed with quartz. Simply put, the formula is 3.1 x the weight in water, minus 1.9 x the weight in air:

 

Wet nugget weighs 74.5 grams x 3.1 = 230.95
Dry nugget weighs 96 grams x 1.9 = 182.4

 

230.95 - 182.4 = 48.55
31.1 = number of grams per ounce
48.55 / 31.1 = 1.56 ounces of gold

 

Original dry weight = 96 grams / 31.1 = 3.08 ounces.
Subtract the difference between the wet and the dry:
3.08 ounces - 1.56 ounces = 1.52 ounces.
Therefore what is left is 1.52 ounces of quartz.

 

"Wet" = weight in water - Put container of water (enough water to cover nugget) on scale. Tare (zero) out scale. Hang nugget by string in water. Note weight.

 

The specific gravity for gold is 19.3.
The specific gravity for quartz is 2.65.
The ratio between gold and quartz is 7.28 X.

 

Specific Gravities of Common Metals

 

Metal Symbol Specific Gravity Melting Point (° F) Melting Point (° C)
Copper Cu 8.96 1981 1083
Gold Au 19.32 1945 1063
Iron Fe 7.87 2802 1539
Lead Pb 11.34 621 327
Nickel Ni 8.90 2651 1455
Palladium Pd 12.00 2831 1555
Platinum Pt 21.45 3224 1773
Silver Ag 10.49 1761 961

 

Pure gold has a density of 19.32 gm/cm3 while 14K gold has a density between 12.9 and 14.6 gm/cm3, depending upon the composition of the alloy.

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