Lapis Lazuli Vs Sodalite

How to Tell Lapis Lazuli from Sodalite

Although lapis lazuli and sodalite can be a similar colour, telling one from the other is usually quite easy. 

Although sodalite is best known for being blue, it also occurs in other colours. Blue, however, is far more common.

Lapis lazuli only occurs in blue, although the shade can vary slightly depending on the grade.

Lapis lazuli is a rock, not a mineral, because it's made up of several different minerals, one of which is sodalite. 
The easiest way to tell lapis lazuli from sodalite is by looking for inclusions of pyrite. These golden speckles are found in most, but not all, lapis lazuli, regardless of grade.

Although pyrite and sodalite can form in similar geological environments, pyrite inclusions are far less common in sodalite than in lapis lazuli. 

Pyrite, also known as iron pyrite and Fool's Gold, is an iron sulphide mineral, which means it's a chemical compound of iron and sulphur.  

Interestingly, pyrite is an inclusion within the mineral lazurite. Lazurite, which is always present in lapis lazuli, is also responsible for the stone's blue colour.

The amount of pyrite in lapis lazuli can vary considerably.
Inclusions of white calcite, which are common in lapis lazuli, can sometimes give the stone a slightly mottled appearance.

Although calcite can also be an inclusion in sodalite, it looks quite different. The finest grade blue sodalite can be relatively free from inclusions.

In this next photo, the sodalite tumbled stones on the left, are a high grade. The stones on the right are included with calcite.

Although inclusions in sodalite can give the stone an interesting appearance, the presence of another mineral lowers the grade. 
Calcite inclusions can be seen in the lapis lazuli stones in this next photo, but it's far more grey. You'll also notice the stone's colour is more navy blue.     

Sodalite can also feature an orange inclusion, which may be calcite or feldspar or may come from staining or oxidation. 

Blue sodalite is far more common than lapis lazuli and can be found in several countries. Therefore, commercial-grade stones are much cheaper.

Calcite inclusions in sodalite, which are relatively common, tend to be white, greyish-white or orange.

When comparing two stones of a similar size, lapis lazuli would be heavier than sodalite and depending on the grade, should also be more expensive.

If you're still unsure, the next option would be a scratch test, but scratching a nice stone purely for identification purposes should always be the last resort.

Article Photos

The lapis lazuli and sodalite in our photos are from our collection. Photos 2, 3 and 4 are clickable. 

Pop-up photos: Sulphur, lazurite, sodalite on calcite - Courtesy of Géry Parent. Calcite - Courtesy of Stan Celestian.