Why your vendor matters: properties vary by mine layer (Kovalevski / Rozhkova)

Stones from different vendors can behave quite differently in conductivity tests, density, and water-prep performance. Why? Because they were quarried from different stratigraphic layers of the same Karelian deposit, and those layers are not chemically identical.

This study measures carbon content, density and electrical conductivity by mine layer in the Zaonega Formation. It is the empirical backing for what experienced buyers already say: source / vendor / batch matters more than grade label.

When you are doing the multimeter conductivity test or the density check on a new stone, results varying between batches from the same vendor are expected, not a sign of fraud.

Sources: Kovalevski, Rozhkova et al., Physical and chemical properties of shungite rocks from different stratigraphic levels of the Zaonega Formation. ResearchGate publication 339523021 .

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.