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Ohaus Scales

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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

	Sapphire 10 Weighs in grams, carats and pennyweights. 50 carat at .01 carat. 10 grams at .002 gr.  9730 Buy Price $459
	AV612N Legal Meets legal requirements for weighing metal bought and sold. Weighs in grams, pennyweights, ounces & troy ounces. Max capacity 610 grams at .1 gram precision.  9836 Buy Price $625
	Specific Gravity Scales Specific gravity measurement can be used for doing very rapid and accurate assays of the jewelry you make.  Specific gravity is the ratio of weight of a volume of substance to the weight of an equal volume of water.  There is a hook on the bottom of these scales that allows you to suspend a piece of jewelry by thread into a beaker of water below the scales.  Specific gravity measurement can be used for doing very rapid and accurate assays of the jewelry you make.  These are special order items, not stock, not returnable.    See: Related Shor Web Page: Assaying SP 202 Capacity 200 gram at .01 gram. Weighs in gram, pennyweight, ounce, troy ounce. Parts counter. Has a weigh below hook for measuring specific gravity and an easy access bracket for securing the balance. Specific gravity measurement can be used for doing very rapid and accurate assays of the jewelry you manufacture. 9962-PRO Buy    Price $329.95 SP 401 Capacity 400 gram at .1 gram. Weighs in gram, pennyweight, ounce, troy ounce. Parts counter. Has a weigh below hook for measuring specific gravity and an easy access bracket for securing the balance.     9965-PRO Buy    Price $229.99 SP 601 Capacity 600 gram at .1 gram. Weighs in gram, pennyweight, ounce, troy ounce. Parts counter. Has a weigh below hook for measuring specific gravity and an easy access bracket for securing the balance.   9964 Buy     Price $264.99

 

What is Specific Gravity?

The Specific Gravity Test (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.

What is specific gravity? Specific gravity is simply the weight in grams of one cubic centimeter of a metal. Here are specific gravities and other properties of a few more metals:

Metal	Symbol	Specific Gravity	Melting Point (ºF)	Melting Point (ºC)
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/cm^3 while 14k gold has a density between 12.9 and 14.6 gm/cm^3,  depending upon the composition of the alloy

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