Judging quality
A horsetail inclusion is diagnostic of Russian origin. Namibian stones are cleaner and more yellow-green. Look for that unmistakable dispersion in a spot light.
Garnet
Demantoid Garnet
Andradite garnet with dispersion higher than diamond — a green stone that throws visible rainbow fire. Russian Ural material often contains the golden 'horsetail' inclusion of byssolite fibres, which raises rather than lowers value.
Care
Slightly softer than most gem garnets; avoid abrasive settings and ultrasonics.
History & lore
Fabergé used Ural demantoid heavily in the 1890s, and the stone was largely unavailable for most of the twentieth century after the Russian workings closed.
Cultural history, recorded as tradition rather than as medical or scientific claim.
Common questions about Demantoid Garnet
- What is Demantoid Garnet?
- Andradite garnet with dispersion higher than diamond — a green stone that throws visible rainbow fire. Russian Ural material often contains the golden 'horsetail' inclusion of byssolite fibres, which raises rather than lowers value.
- How hard is Demantoid Garnet and what is it made of?
- Demantoid Garnet is a Garnet-family mineral with the composition Ca3Fe2(SiO4)3. It crystallizes in the cubic system and rates 6.5-7 on the Mohs hardness scale. It occurs in green, apple green, emerald green.
- Where does Demantoid Garnet come from?
- Notable localities for Demantoid Garnet include Ural Mountains, Russia, Namibia, Madagascar, Iran.
- How do you tell good Demantoid Garnet from filler?
- A horsetail inclusion is diagnostic of Russian origin. Namibian stones are cleaner and more yellow-green. Look for that unmistakable dispersion in a spot light.
- How do you care for Demantoid Garnet?
- Slightly softer than most gem garnets; avoid abrasive settings and ultrasonics.
See it in person
Photographs only go so far
Both rooms are open six days a week, and there is always someone happy to pull pieces out of the case so you can compare them under the light.