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.
Stock # 9730
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.
Stock # 9836
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.
Stock # 9962-PROPrice
$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.
Stock # 9965-PRO 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.
Stock # 9964 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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