Jade, Jadeite or lookalikes - measuring its SG!
Different Gemstones have different values of specific gravity (SG).
Therefore if we know the SG of the green stone; we can rule out whether it could be Jade or not.
There are two ways to determine the specific gravity of Jade | Jadeite; namely heavy liquids method and hydrostatic method.
Heavy Liquids Method
 HeavyHeavy liquids are substances in liquid form that have a known Specific Gravity (SG) and are used as a means of quick separation of stones with similar appearance. In general, these liquids are highly toxic and precautions should be taken when used. Always use heavy liquids in a well-ventilated environment.
- If the jade sinks, its SG > SG of the liquid.
- If the jade floats, its SG < SG of the liquid.
- If the jade remains suspended (neither sinks nor floats), its SG equals the SG of the liquid.
4 types of liquids are used in gemology:
- Methylene Iodide (SG=3.33)
- Methylene Iodide diluted with Toluol (SG=3.05)
- Bromoform (SG=2.85)
- Bromoform diluted with Toluol (SG=2.65)
Methylene Iodide (CH2l2) also known as di-idiomethane has a SG of about 3.33. Jadeite Jade (SG=3.33) will suspend or slowly sink in this liquid while Nephrite Jade (SG=2.95 ) will float.This is one of the fastest way to distinguish between Jadeite Jade and Nephrite Jade even Jadeite lookalikes.
  
Hydrostatic Equipment Method
The tools that you use are entirely up to you. Regardless of your setup, the principles will remain the same.
(1) Weigh the jade in air.
(2) Weigh the jade suspended in water.
(3) Put these two weight values into a formula that gives the specific gravity.
Weigh the jade in air.
Get a scale with at least 0.01 gram accuracy.
Turn scale on and wait for the reading to go to zero.
Clean the Jade and dry it.
Record the weight of the jade.
Weigh the jade suspended in water.
Turn scale on and wait for the reading to go to zero.
Setup whatever tools you are using so that you can suspend the jade in water and place it on the scale.
Press the "Tare" button on your scale so the reading will go to zero.
Gently place your jade onto the surface in the water such that the jade is completely submerged and suspended.
Usually you should give the setup and the water some time to stop moving or shaking.
Record the weight of the jade.
Calculate Specific Gravity
Take the air weight of the jade and the water weight of the jade and put them into the formula shown below.
( AIR WEIGHT )
(AIR WEIGHT) - (WATER WEIGHT)
For Example: If the air weight is 5.46 grams and the water weight is 3.81 grams then the formula will be as follows:
( 5.46 )
( 5.46 ) - ( 3.81 )
The Specific Gravity equals 3.31. (Jadeite has a SG of 3.3-3.4)
Listed below are other Jadeite lookalikes and its SG for your references.
| Name |
Color |
SG |
| Nephrite |
Dark Green, White |
2.9-3.1 |
| Serpentite Jade |
Yellowish Green, White, Apple Green |
2.58- 2.62
|
| Hydro-Grossular |
Green, Yellowish Green |
3.48
|
| Aventurine Quartz |
Green |
2.66 |
| Chalcedony |
Green |
2.60 |
| Agalmatolice |
Light Green, Yellowish Green |
2.80 |
| Saussurite |
Dark Green with white spots |
3.20 |
| Amazonite stone |
Bluish Green |
2.56
|
| Chrysoprase |
Apple Green |
2.66 |
| Dyed Quartzie |
Fresh Green |
2.65 |
| Green Glass |
Evenly Green |
2.49-2.70
|
| Albite |
White |
2.64 |
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