Russia – Ural Gem Deposits Overview
Ural Mountains gem belt – demantoid garnet, alexandrite, emerald; Yakutia diamond; serpentinite and mica-schist geological settings.
Introduction
The Ural Mountains of Russia host one of the world's most remarkable concentrations
of rare and collectible gem varieties: demantoid garnet (the finest andradite), the
benchmark alexandrite (the standard of colour-change quality), and Ural emerald from
the Malyshevsky deposit. The Ural belt stretches ~2,500 km and formed during
Late Palaeozoic (350–290 Ma) suturing of the Russian and Siberian plates.
Russia also hosts the world's largest diamond production by volume in Yakutia
(Sakha Republic, eastern Siberia) – geographically and geologically distinct
from the Ural gem belt.
Geological Settings
| Setting | Location | Gems Produced |
|---|---|---|
| Serpentinised ultramafic bodies | Central/south-central Urals | Demantoid garnet, chrysotile serpentine |
| Mica-schist / phlogopite contact zones | Tokovaya River district | Alexandrite, emerald |
| Kimberlite pipes | Yakutia / Sakha Republic (eastern Siberia) | Diamond (Russian diamond) |
Demantoid Garnet – Brief Overview
- Discovered 1860s; Bobrovka River and Sysert area, Sverdlovsk Oblast
- Andradite garnet (Ca₃Fe₂(SiO₄)₃), Cr³⁺-coloured; highest dispersion of
any natural garnet (0.057 – exceeds diamond 0.044) - "Horsetail" inclusion is the single most diagnostic Ural feature
- See dedicated file: origin/russia/demantoid
Alexandrite – Brief Overview
- Discovered 1830; Tokovaya River district, ~80 km east of Yekaterinburg
- Named for Tsarevich Alexander (later Tsar Alexander II)
- Russian alexandrite = global benchmark for colour-change quality
- See dedicated file: origin/russia/alexandrite
Ural Emerald – Brief Overview
- Izumrudnye Kopi (Emerald Mines) + Malyshevsky deposit; ~90 km NE of Yekaterinburg
- Phlogopite mica inclusions are most diagnostic feature for Ural provenance
- Cr³⁺ + V³⁺ chromophores; mica-schist host at granite contact
- See dedicated file: origin/russia/emerald
Russian Diamond (Yakutia)
Russia is the world's largest diamond producer by volume (Alrosa company operations):
- Mir pipe (Mirny): Discovered 1955; one of the largest kimberlite pipes;
underground mining continues - Udachnaya, Aikhal, Jubilee pipes (Nyurba field): Major modern producers
- Russian Yakutian diamonds show the standard kimberlitic inclusion suite
(olivine/forsterite, pyrope garnet, chrome diopside, graphite) – no unique
macro-diagnostic features that distinguish them from other kimberlitic origins
at the gemmological bench level - Separation from HPHT or CVD synthetic diamond uses standard spectroscopic
methods; origin determination of individual natural diamonds is not routinely
possible