Can you mail radioactive, asbestos or mercury minerals?
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Not on your own judgment. USPS Publication 52 prohibits all radioactive material by domestic air and allows only narrow categories by surface mail, within activity limits and a surface radiation limit of 0.5 millirem per hour, with marking requirements [1]. A Department of Transportation exclusion for natural materials and ores has an activity ceiling that only measurement can check [6]. Asbestos is listed by USPS as a hazardous material but is not among the Class 9 items it names as mailable [3], and metallic mercury is nonmailable [4]. No source read for this page confirms that any radioactive, asbestiform or mercury specimen may be mailed. This page reports each rule and what to ask.
Radioactive specimens: USPS Publication 52, section 347
USPS defines radioactive material by reference to 49 CFR 173.403, "any material containing radionuclides," with activity thresholds set by 49 CFR 173.436 and 173.433 [1]. Section 347, as read in October 2026 (the section page shows no edition date), says:
| Route | What section 347 says |
|---|---|
| Domestic air | "All radioactive materials are prohibited" (347.21) [1] |
| Domestic surface | Packages bearing a White-I, Yellow-II, Yellow-III or Fissile label are prohibited. Mailable packages must stay within the Exhibit 347.23 activity limits and fall under UN2910 (limited quantity, excepted package), UN2911 (instruments and articles such as clocks and electronic tubes) or UN2909 (articles containing only natural or depleted uranium or thorium) [1] |
| International | Items bearing or required to bear a Class 7 label are prohibited, and "The radioactive activity content must not exceed one-tenth of the limits outlined in" Exhibit 347.23 [1] |
| Any package | "Packages bearing, or required to bear, any Class 7 hazardous materials warning label for radioactive materials" are nonmailable (347.22) [1] |
| Packaging | Packaging Instruction 7A; for domestic mail "the radiation level at any point on the external surface of the mailpiece must not exceed 0.5 millirem per hour" (347.3) [1] |
| Marking | "Radioactive" on the primary receptacle or secondary packaging, and a conformance statement on the address side citing 49 CFR 173.421 (UN2910), 173.424 (UN2911) or 173.426 (UN2909) (347.4) [1] |
| Proof | "The mailer must provide accurate documentation verifying activity levels do not exceed permissible limits" when USPS asks (347.23) [1] |
Section 347 mentions natural uranium and thorium only in the context of manufactured articles (UN2909) and does not mention ores, minerals or specimens [1]. Whether an autunite or uraninite specimen fits any mailable category, and how a seller would document its activity, is not answered by the text. The radiation limit is measured, so a seller without calibrated measurement cannot show compliance.
The DOT natural-material exception
The federal Hazardous Materials Regulations' radioactive subpart opens its list of exclusions with "This subpart does not apply to:" and paragraph (b)(4) of 49 CFR 173.401 names "Natural material and ores containing naturally occurring radionuclides" that are in their natural state, or processed only for purposes other than extracting the radionuclides, and not intended to be processed for their use [6]. The exclusion holds only while the material's activity concentration does not exceed 10 times the exempt material activity concentration values in 49 CFR 173.436, or values determined under 173.433 [6]. PHMSA's Interpretation 17-0114 (letter dated February 27, 2018, published March 6, 2018) adds a definition of natural material as "material existing in a form as it would otherwise be in nature, not in a form manipulated by human application" [2].
The question PHMSA answered was whether drilling mud qualified, and its answer was "The answer is no" [2]. The letter does not mention mineral specimens. It is not a ruling that specimens are excepted. Relying on the exclusion would take a measured activity concentration, which most sellers do not have, and the exclusion is a DOT rule that does not override what USPS accepts in the mail.
A separate exemption from Nuclear Regulatory Commission licensing (10 CFR 40.13) applies to possessing unrefined ore, and it says nothing about shipping. Do not mail a radioactive specimen on the strength of it; the NRC side is explained on radioactive minerals at home.
Asbestiform specimens
The National Park Service records two United Nations shipping numbers for asbestos minerals: UN2590 for "white asbestos" (chrysotile, with tremolite, actinolite and anthophyllite grouped with it) and UN2212 for amosite and crocidolite [5]. USPS Publication 52 section 349 lists asbestos among its examples of Class 9 miscellaneous hazardous materials, "not all of which are mailable," and names as mailable only "lithium batteries, dry ice, magnetized materials and items that can qualify as consumer commodity materials" [3]. Asbestos is not on that list. The text does not say in a single sentence that asbestos is nonmailable, but it gives no route to mail it. The habit matters: a bladed, non-fibrous actinolite crystal is a different material from fibrous asbestiform actinolite, as asbestiform minerals explains, but no carrier source read for this page draws that line for shipping.
Mercury and mercury minerals
USPS section 348 lists "Mercury and Mercury-Containing Devices (UN2809)," including metallic mercury, as nonmailable (348.21) [4]. Only manufactured devices with very small amounts of mercury (UN3506) are mailable, within per-device and per-package limits [4]. Section 348 does not mention mercury minerals such as cinnabar. NPS notes that "Mercury vapor is readily liberated from the mineral cinnabar" and that it "may have elemental (liquid) mercury associated with it" [5]. A cinnabar specimen with visible droplets of native mercury contains metallic mercury. Whether a cinnabar specimen without visible mercury is mailable was not confirmed.
Private carriers
UPS, FedEx and DHL each publish their own hazardous materials rules. Their current terms for radioactive, asbestos and mercury items were not read for this page. Ask the carrier's hazardous materials desk in writing.
What this means in practice
| Specimen | Status from the sources read | What to do |
|---|---|---|
| Uranium or thorium minerals (autunite, torbernite, uraninite, thorite and others) | Prohibited by domestic air; surface only if within section 347 categories and limits, which do not mention specimens [1] | Do not mail without written confirmation from USPS or PHMSA for your case. Sell for local pickup or at shows |
| Asbestiform minerals | Class 9 with UN numbers [5]; not on USPS's mailable Class 9 list [3] | Do not mail. Sell locally, sealed and labeled |
| Native mercury or cinnabar with visible mercury | Metallic mercury nonmailable [4] | Do not mail |
| Cinnabar without visible mercury, other mercury minerals | Not addressed [4] | Ask USPS in writing before mailing |
| Arsenic, lead and other toxic-element minerals | Not addressed in the sections read | Pack sealed and labeled; read Publication 52 section 346 (toxic substances) and ask USPS if in doubt |
Questions to send USPS or PHMSA
Write to USPS and to PHMSA with: the species, the mass, a measured surface dose rate if you have one, the route (air, surface, international), and the packaging you intend. Ask which category, if any, the specimen fits, and keep the reply with the shipment record.
When you cannot ship it
A specimen that cannot be mailed can still be sold, to a buyer who collects it in person or at a show, with handling instructions on the label. If you decide not to keep it, getting rid of hazardous specimens covers who to call and what not to do.
References
- United States Postal Service, *Publication 52, Hazardous, Restricted, and Perishable Mail*, section 347 Radioactive Materials (no edition date on the section page), read October 22, 2026. https://pe.usps.com/text/pub52/pub52c3_026.htm
- Pipeline and Hazardous Materials Safety Administration, Interpretation 17-0114, letter to Terry R. Myers, PHI Inc., dated February 27, 2018, published March 6, 2018. https://www.phmsa.dot.gov/regulations/title49/interp/17-0114
- United States Postal Service, *Publication 52*, section 349 Miscellaneous Hazardous Materials (Hazard Class 9), read October 22, 2026. https://pe.usps.com/text/pub52/pub52c3_028.htm
- United States Postal Service, *Publication 52*, section 348 Corrosives (Hazard Class 8), read October 22, 2026. https://pe.usps.com/text/pub52/pub52c3_027.htm
- National Park Service, Greg McDonald, *Health and Safety Issues with Geological Specimens*, Conserve O Gram 11/11, September 2006. https://www.nps.gov/subjects/museums/upload/11-11_508.pdf
- eCFR, 49 CFR 173.401 Scope (Part 173, Subpart I, Class 7 (Radioactive) Materials), up to date as of October 20, 2026, read October 22, 2026. https://www.ecfr.gov/current/title-49/subtitle-B/chapter-I/subchapter-C/part-173/subpart-I/section-173.401
