The mass-market shungite trade tends to talk about "regular" shungite (Sh-III) and "élite" shungite (Sh-I). There's a third grade in the Russian tradition that almost nobody outside Karelia knows about:
Petrovsky shungite.
What it is
Petrovsky shungite is a specific intermediate-carbon variety, named in Peter the Great's honour by the regional miners. Carbon content is in the range of about 50–80 wt%, between regular Sh-III (~30%) and élite Sh-I (~95%). It has the dark colour of standard shungite but a denser, more lustrous appearance.
It is the variety that Russian tradition associates most strongly with the soldier-stone story, the kind of rock that was supposedly carried in army kits during the Northern War campaigns. The connection to Peter is geographic and historical: Peter's mining operations in Olonets (the same operations that produced cannons, anchors, and pig iron for the Russian navy) crossed Petrovsky shungite seams, and the rock was named in his honour by the foundry workers and miners.
Why it's rare
The specific compositional sweet spot, high carbon but not Sh-I élite, only occurs in limited layers. Most carbon-rich shungite at the Karelian deposits is either pure-élite Sh-I in small pockets, or moderate Sh-II/Sh-III in vast quantities. The Petrovsky middle ground is geologically uncommon.
Properties
Unlike Sh-I élite, which is essentially glassy carbon and chemically inert in water, Petrovsky shungite still has enough silica-aluminosilicate matrix to interact with water during prolonged contact. So it bridges the gap: more durable and visually striking than standard Sh-III, but still chemically active in the way that Sh-I is not.
This makes it a sought-after grade for users who want a piece they can use as both a personal-carry stone and a water-treatment piece, a single object serving both purposes.
Sources
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Skyline Minerals: Petrofsky Shungite
, vendor reference describing the grade and its naming.
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The Story of the Most Unique, Yet Unknown Type of Shungite, Petrovsky Shungite (Karelian Heritage)
, extended write-up on the variety and its historical naming.
Editor's note (2026 audit): Petrovsky carbon range '50-80%' is generous; vendor consensus is 50-75% Suggested edit: Tighten to ~50-75% to match karelianheritage.com vendor consensus
Edited 2026-05-03, source audit. Cited sources verified to exist; no fabricated sources detected. Where the audit could directly read the source (live English-language papers, open Russian academic articles), claims were compared against the source content and corrections applied above. Where sources were paywalled or geo-blocked at audit time, bibliographic plausibility was verified via parallel routes (publisher index pages, PubMed/PMC mirrors, cross-citations) but the source content itself was not always directly read. If a specific claim matters to you, click the source link and verify it yourself.
