Russian Chrome Diopside — Yakutian Green from the Permafrost
Russian Chrome Diopside — Yakutian Green from the Permafrost
The dominant commercial source of chromium-coloured diopside, mined in eastern Siberia
Russian chrome diopside is the trade name for chromium-coloured diopside mined principally at the Inagli deposit in the Sakha Republic (Yakutia), Siberia. The material is the world's primary commercial source of gem-quality chrome diopside and has occupied a recognisable price tier since deposits were brought to market in the late 1980s. Colour at its best rivals tsavorite garnet and fine emerald in saturation, but the geology of the deposit imposes a sharp ceiling on size and a corresponding ceiling on price.
Composition and colour
Diopside is a calcium-magnesium clinopyroxene, CaMgSi2O6, monoclinic, with hardness 5.5 to 6.5 and refractive indices around 1.664 to 1.730. The chrome variety takes its colour from substitution of chromium for magnesium and aluminium in the structure. Yakutian rough is typically vivid emerald-green to slightly bluish-green, with strong saturation in stones under one carat and a tendency toward over-darkening at larger sizes — the body colour intensifies with depth, so cutters favour shallow brilliants and barion shapes that hold light return without crossing into blackness.
Pleochroism is moderate: dichroic in green and yellow-green axes. Inclusions are typically minor — most Yakutian rough cuts eye-clean, which is part of the variety's commercial appeal at modest prices.
The Inagli deposit
The Inagli massif sits in continuous permafrost in the Sakha Republic, north of Aldan. The host rock is a chromium-rich ultramafic complex, and chrome diopside occurs in coarse-grained pyroxenite and dunite veins. Mining is seasonal — the working window is short, ground conditions are difficult, and the deposit produces mostly small rough. Faceted goods over two carats are scarce in the market; over three carats, prices climb steeply, and over five carats the material moves out of its commercial tier and into the collector market.
Smaller deposits exist in Pakistan, Myanmar, Finland, and Canada, but Yakutian production has dominated commercial supply since the 1990s. Trade reference to Russian chrome diopside almost always implies Inagli rough.
In the trade
Chrome diopside fills a clear gap in the green-stone market: it is the most affordable saturated green stone after peridot and is meaningfully greener than most peridot. Calibrated melee in 1 to 4 mm sizes is widely available and is used in pavé and accent work. Single stones in the half-carat to one-carat range are the workhorse size. The variety is rarely treated — heating is not commercially applied — so disclosure issues are simpler than for emerald or aquamarine.
The principal commercial caveat is hardness. At 5.5 to 6.5 with directional cleavage, chrome diopside is not a daily-wear ring stone in unprotected settings. We set it readily in pendants and earrings, and in ring work we prefer bezels or low-profile halo designs that shield the table and girdle from impact.
Identification and disclosure
Standard refractive index, specific gravity (3.22 to 3.38), and spectroscope examination separate chrome diopside from tsavorite, chrome tourmaline, and emerald without difficulty. Strong chromium absorption in the red and a 505 nm doublet are diagnostic. Laboratory reports for chrome diopside are uncommon outside the high end of the market; for a saturated stone above two carats, an identification report from a recognised laboratory adds confidence at modest cost.
Care
Clean with mild soap and warm water and a soft brush. Avoid ultrasonic and steam cleaning because of cleavage and the moderate hardness. Store separately from harder stones to prevent surface scratching during transport.