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Below is a process to determine the specific gravity of any
metallic material such as Gold, Silver, etc) , the specific gravity
number in turn will provide you with the identity of the material.
This is an extremely delicate test. If the weights are not determined correctly and accurately, you will get an incorrect specific gravity number. This example uses a White Gold Ring to run the test. Any item used for a test must not have any gem stones or other objects embedded in the material or the measurements will be incorrect and not useable. Any plating on the object under test will also will also influence the final result.
w1 = weight 1 (weight of object in air)
w2 = weight 2 (weight of object in water)
You will need a scale calibrated in grams to determine the weights.
Step 1: Weigh the item (W1) before you put it in the water (connect the ring by a very fine thread to the scale). See photo below.
(weight 1 = 3.8362 grams)
Step 2: Weigh the item in the water. (weight 2) See photo below.
Step 2a: Filled a glass container with water
Step 2b: Attach the item to be weighted to the scale by a very fine thread and place the item in the container of water.
Note: The item must not touch the container sides. (weight 2 = 3.5251 grams).
Step 3: Record both weights. (W1 & W2)
Step 4: Complete the calculation below.
The example below uses the White gold ring results in the example above to calculate the specific gravity.
Step 5: Take (w1 minus w2) w1 – w2 = wd (weight difference)
Use weights recorded in steps 1 through 5
Gold ring’s weight in the air (w1) 3.8362 grams (w1)
Gold ring's weight in the water (w2) 3.5251 grams (w2)
Subtract the weight in the water (w2) from the weight in the air (w1) the result is wd = 0.3111 grams (weight difference)
Step 6: Use the following formula w1 / wd = specific gravity
(Divide w1 air measurement by wd weight difference to find the specific gravity)
W1 = 13.8362 grams divided by Wd = .3111 grams = 12.33 specific gravity
The chart below indicates a White's Gold Ring Specific Gravity should be 12.61 the different specific gravity achieved in the test is probably due to the rings gold purity and the additional thread length used in the W2 test. These two variables will effect the final specific gravity accuracy of the measurement.
12.33 is the specific gravity of the White Gold ring
Check the result achieved in the test to in the Specific Gravity Table below.
Specific Gravity Table
Metal Specific Gravity
Gold 19.32
18K Green 15.90
18K Yellow 15.58
18K White 14.64
18K Red 15.18
14K Green 14.20
14K Yellow 13.07
14K White 12.61
14K Red 13.26
10K Green 11.03
10K Yellow 11.57
10K White 11.07
10K Red 11.59
.999 Pure Silver 10.50
Sterling Silver 10.36
.925 Sterling 10.31
German Silver 8.74
Platinum 21.45
Platinum 21.45
Platinum 15% Iridium 21.59
Platinum 10% Iridium 21.54
Platinum 5% Iridium 21.50
This is an extremely delicate test. If the weights are not determined correctly and accurately, you will get an incorrect specific gravity number. This example uses a White Gold Ring to run the test. Any item used for a test must not have any gem stones or other objects embedded in the material or the measurements will be incorrect and not useable. Any plating on the object under test will also will also influence the final result.
w1 = weight 1 (weight of object in air)
w2 = weight 2 (weight of object in water)
You will need a scale calibrated in grams to determine the weights.
Step 1: Weigh the item (W1) before you put it in the water (connect the ring by a very fine thread to the scale). See photo below.
(weight 1 = 3.8362 grams)
Step 2: Weigh the item in the water. (weight 2) See photo below.
Step 2a: Filled a glass container with water
Step 2b: Attach the item to be weighted to the scale by a very fine thread and place the item in the container of water.
Note: The item must not touch the container sides. (weight 2 = 3.5251 grams).
Step 3: Record both weights. (W1 & W2)
Step 4: Complete the calculation below.
The example below uses the White gold ring results in the example above to calculate the specific gravity.
Step 5: Take (w1 minus w2) w1 – w2 = wd (weight difference)
Use weights recorded in steps 1 through 5
Gold ring’s weight in the air (w1) 3.8362 grams (w1)
Gold ring's weight in the water (w2) 3.5251 grams (w2)
Subtract the weight in the water (w2) from the weight in the air (w1) the result is wd = 0.3111 grams (weight difference)
Step 6: Use the following formula w1 / wd = specific gravity
(Divide w1 air measurement by wd weight difference to find the specific gravity)
W1 = 13.8362 grams divided by Wd = .3111 grams = 12.33 specific gravity
The chart below indicates a White's Gold Ring Specific Gravity should be 12.61 the different specific gravity achieved in the test is probably due to the rings gold purity and the additional thread length used in the W2 test. These two variables will effect the final specific gravity accuracy of the measurement.
12.33 is the specific gravity of the White Gold ring
Check the result achieved in the test to in the Specific Gravity Table below.
Specific Gravity Table
Metal Specific Gravity
Gold 19.32
18K Green 15.90
18K Yellow 15.58
18K White 14.64
18K Red 15.18
14K Green 14.20
14K Yellow 13.07
14K White 12.61
14K Red 13.26
10K Green 11.03
10K Yellow 11.57
10K White 11.07
10K Red 11.59
.999 Pure Silver 10.50
Sterling Silver 10.36
.925 Sterling 10.31
German Silver 8.74
Platinum 21.45
Platinum 21.45
Platinum 15% Iridium 21.59
Platinum 10% Iridium 21.54
Platinum 5% Iridium 21.50
Updated: November 05-2019