Specific gravity

Much of our jewelry is designed using Cad-cam software. With this software we can determine how heavy a piece of jewelry 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 discovered is what we now know as Archimedes' principle: Volume = Mass / specific gravity, which means that:

An object submerged in a fluid or gas experiences an upward force equal to the weight of the fluid or gas it displaces.

Therefore, the difference in weight equals the weight of the water displaced. By dividing this weight by the density of water (1 kg per cubic decimeter), we find the volume of the object. Multiply this volume by the density of gold to calculate the actual weight of the crown. In this case, it turned out to be a silver-plated crown.

Specific gravity precious metals