Identifying Gem Stones – Step 2:

Hardness:

In the identification of gem stones, hardness is one of the most important of all tests. While not usually a definitive way to identify a gem stone, it does at least put you into the correct group of possibilities.

To help you use hardness to identify a gem stone, there are a variety of hardness scales that you can use. The most common is the 'Mohs' Scale' which ranks mineral hardness on a scale of one (talc) to ten (diamond).

To measure the hardness of the gem stone you wish to identify, you will use a hardness kit. This contains a set of substances of varying hardness keyed to one of the hardness scales.

If your test substance can scratch the subject gem stone, then the test substance is harder than the subject gem stone. By trying several test substances on your subject gem stone, you will be able to approximate the hardness of the subject.

Since diamond is often too expensive for most kits, glass is sometimes used in its place.