Much of our jewellery is designed using Cad-cam software. With this software we can determine how heavy a piece of jewellery is by using specific gravity. Below you can see that there is a considerable difference between the specific gravity of silver and gold. Gold has a specific gravity of 19.3 in its pure form and thus feels heavier than pure silver which has a specific gravity of 10.5. The specific gravity can also be used to test whether something is silver or gold.
An example of this is the Archimedes water test. Archimedes was a Greek scientist in the 3rd century BC. King Hiero II asked him to test a gold crown for authenticity. He of course couldn’t damage the crown.. After pondering for a long time he thought of a solution for this problem in his bathtub. Enthusiastically he jumped out of his tub and ran through the streets naked screaming ‘Eureka, eureka’. What he found was what we now know as the law of Archimedes: Volume = mass / specific gravity.
The crown was first normally weighed and afterwards it was weighed in a container of water. After this he divided the normal weight by the difference between both weightings. This resulted in the specific gravity of the object. In this case it was a silver gilded crown.
| Pure gold | 19.3 |
|---|---|
| 22 carat yellow gold | 16.5 |
| 18 carat yellow gold | 15.4 |
| 18 carat red gold | 15.1 |
| 18 carat white gold | 14.8 |
| 14 carat yellow gold | 13.7 |
| 14 carat red gold | 13.1 |
| 14 carat warm yellow gold | 13.4 |
| 14 carat rose gold | 13.3 |
| 14 carat white gold | 12.8 |
| 9 carat yellow gold | 11.1 |
| 9 carat white gold | 10.7 |
| Pure silver | 10.5 |
| Silver 925 | 10.3 |
| Silver 835 | 10.2 |