How shungite blocks EMF: the physics of conductive carbon-mineral composites

Why does a black mineral with a few percent carbon block radio frequencies? The physics is surprisingly clean.

Faraday cage logic

A Faraday cage works because conductive materials have free electrons. When an electromagnetic wave hits a conductive surface, those free electrons rearrange themselves to cancel the field inside the conductor. The wave is reflected, absorbed, or both, but does not pass through.

The degree of shielding depends on:

1. Conductivity of the material
2. Thickness of the shielding layer
3. Frequency of the EMF being shielded against
4. Geometry of the shielding (continuous vs holes/gaps)

Shungite as a Faraday material

Shungite carbon (C-sh) conducts at ~10⁵ S/m at room temperature. That puts it in the metallic-conductor range, comparable to graphite, four orders of magnitude better than ordinary mineral rocks.

What's unusual is the structure. Shungite is a composite: conductive carbon networks (graphite-like packets, graphene fragments, fullerene-like globules) embedded in an insulating silica-aluminosilicate matrix. At carbon contents above ~28-32 wt%, the carbon network percolates, the conductive carbon paths connect through the rock as a continuous web. Below that threshold, the silica isolates the carbon and conductivity drops.

Sh-I (98% C), Sh-II (75% C), and Sh-III (30% C) all sit at or above the percolation threshold. They function as electromagnetic shields. Sh-IV and Sh-V (lower carbon) do not shield as effectively.

Frequency-dependent shielding

Different EMF sources operate at different frequencies. Shungite's response varies:

- ELF (50-60 Hz mains-frequency electric and magnetic fields): limited shielding. ELF passes through most non-magnetic materials. Shungite is non-magnetic except for trace iron-bearing inclusions, so ELF shielding is modest.
- RF (kHz to GHz, including WiFi at 2.4-5 GHz, mobile at 0.7-3 GHz): shungite shows substantial attenuation. This is the band where shungite is most effective.
- Microwave (GHz): V. V. Kovalevski's group at the Karelian Research Centre has measured microwave absorption suggestive of superconductivity-like behaviour up to 110 K in some samples. At room temperature, normal metallic-conductor absorption applies.
- Millimetre-wave (26-38 GHz, including 5G frequencies): Antonets et al. (2021) measured thin shungite plates attenuating in this range. Real measured shielding numbers, not theory.

The composite advantage

A solid metal plate also shields RF, better than shungite, on a per-millimetre basis. So why use shungite?

Metal sheets reflect almost all incoming EMF. The reflection itself can create interference patterns and re-radiate energy in unwanted directions. This is why anechoic chambers and EMF-shielded rooms use carbon-loaded composites and absorbing geometries, not bare metal.

Shungite, like other carbon-based shielding materials, absorbs more than it reflects. The carbon network dissipates the EMF energy as heat (at very low rates, undetectable in practical use). For applications where you don't want strong reflections, like a small piece on a phone or near a router, absorption is preferable to reflection.

This is also why shungite works in a way that doesn't disrupt the device's own signal. A metal Faraday cage on your phone would block the phone from working. Shungite damps RF at certain configurations without blocking the phone's outgoing signal entirely, because the shungite is a partial absorber positioned to interact with the field where it counts.

Cyril Smith's measurements

Cyril W. Smith's 2016 frequency measurements (covered in another thread) directly measured the field-blocking effects across several specimens at frequencies from 0.05 Hz to 5 GHz. His findings were qualitatively consistent with the conductive-composite physics outlined above: shungite is most effective in direct contact with the EMF source, less effective at distance, with a coherence-length-dependent effect range on the order of metres.

Sources

- V. V. Kovalevski group, Karelian Research Centre RAS Institute of Geology, primary conductivity and microwave-absorption measurements: digital collection .
- Antonets et al. (2021), millimetre-wave shielding measurements (also covered in EMF Research thread on 26-38 GHz attenuation).
- Cyril W. Smith (2016), "Preliminary Report on Measurements Involving Shungite", frequency-signature measurements.
- Yoshida et al. (Shinshu / Yamaguchi / Kyoto Universities, 2004), paper PDF , independent confirmation of shungite electrical properties.

Editor's note (2026 audit): Same Kovalevski-claim anchoring issues as thread 146. Antonets 2021 26-38 GHz claim is verified. Suggested edit: Same as thread 146 for Kovalevski claims and Yoshida 2004 reference. Antonets 2021 framing is solid (8-15 µm plates reflecting 95±2%, shielding near 100% in 26-38 GHz range).

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.