Inclusions in Demantoid Garnets

Garnets are most commonly thought of as a brownish-red colour.  However, Garnets actually occur in a number of differently coloured species.  All share a similar crystal structure but vary slightly in their chemical compositions.

Here at LGC Lab, we are big fans of the Demantoid Garnet.  Part of the Andradite Group, they get their colour from the element Chromium and come in green, yellowish-green and occasionally yellow.  The name Demantoid originates from the stones “diamond-like” brilliance and dispersion, as they have a RI and dispersion higher than that of diamond. 

One of the most well-known characteristics of Demantoid Garnets is their “horse tail” inclusions.  These inclusions consist of radiating fibres of asbestos like minerals called Chrysotile.  While “horse tail” inclusions are very common in Demantoid Garnets from the Ural Mountains in Russia, they may also be present in nearly all stones except those from Namibia and Madagascar.

Below are a few close-ups of the horse tail inclusions in our Demantoid Garnets.