Which minerals are asbestos, and what do I do with one?
Updated
On this page9
Six minerals are asbestos when they grow as fibers: chrysotile, crocidolite, amosite, anthophyllite, tremolite and actinolite, the list the National Park Service gives in Conserve O Gram 11/11 [1]. A fibrous specimen of any of them should go into a sealable, clearly marked bag so fibers cannot become airborne [1], and it should never be cut, crushed, scraped or picked apart, because that is when asbestos releases fibers [2]. This page helps you recognize an asbestiform specimen, store it, decide whether to keep it, and find the agency that sets disposal rules where you live.
The six names, and why "asbestiform" is the word that matters
"Asbestos" is a commercial and regulatory term for minerals in a fibrous habit (habit is the shape a mineral's crystals grow in). COG 11/11 names six [1]:
| Name on the NPS list | What it is | What to look for |
|---|---|---|
| Chrysotile | A serpentine-group mineral; COG 11/11 groups it under "white asbestos" for shipping [1] | Silky, flexible white to greenish fibers, often in veins |
| Crocidolite | A fibrous variety of riebeckite, per COG 11/11 [1] | Blue fibers; old mine and sample-set material |
| Amosite | A fibrous amphibole | Mostly met in old commercial and school sample sets |
| Anthophyllite | An amphibole; asbestiform only when fibrous | Fibrous masses in metamorphic rock |
| Tremolite | An amphibole that grows both as fibers and as solid crystals | Check every specimen for a fibrous habit |
| Actinolite | An amphibole that grows both as fibers and as solid crystals | Check every specimen for a fibrous habit |
Tremolite and actinolite are the names that confuse people, because both also grow as solid, non-fibrous crystals. A bladed green actinolite crystal is not the same hazard as a tuft of silky actinolite fibers. The hazard follows the habit, which is why a careful label says "asbestiform tremolite" when that is what the specimen is. For shipping, COG 11/11 records two United Nations hazard numbers that follow the same split: UN2590 for "white asbestos" (chrysotile, tremolite, actinolite, anthophyllite) and UN2212 for amosite and crocidolite, which it calls extremely hazardous [1]. What those numbers mean for mailing is on shipping radioactive, asbestos and mercury minerals.
When an asbestos specimen is dangerous
NPS Conserve O Gram 2/11 (September 1999), written for museum staff dealing with asbestos in buildings and collections, gives the principle in one line: "Asbestos is relatively safe until it is crushed, cut, filed, scraped, or otherwise released from binding materials" [2]. Material that "can be crushed by hand pressure alone is called friable" [2], and friable material releases fibers far more easily.
The diseases are lung cancer, mesothelioma and asbestosis [1]. COG 2/11 adds that because fibers stay in the body, "each exposure increases the likelihood of developing an asbestos-related disease," and that "Asbestos-related diseases may not appear until several decades after exposure" [2]. For workplaces, OSHA's permissible exposure limit, as COG 2/11 reported it in 1999, is 0.1 fibers per cubic centimeter of air as an 8-hour time-weighted average [2]. That number binds employers and does not apply in a home; it is given here to show how small a quantity of fiber regulators treat as significant.
What you see, what it means, what to do
| What you see | What it likely means | What to do |
|---|---|---|
| Silky, flexible fibers that separate from the specimen or stand up from its surface | Asbestiform habit; fibers can be released by touch | Do not handle bare-handed or pick at it. Bag it as described below |
| A hard, compact mass with fibrous texture that does not shed | Fibrous mineral bound in a tougher matrix | Lower risk while intact. Box and bag it; never cut, file or crush it |
| Bladed or prismatic green or white crystals labeled tremolite or actinolite, no fibers | Probably non-asbestiform | Store normally, but check with a loupe for fibrous areas before deciding |
| An old school or industrial sample card labeled "asbestos" | Likely a real asbestos sample, often friable | Leave it in its packet, bag the whole card, and do not open the packet |
| Loose fibers in a drawer or box | Fibers already released | Do not sweep, brush or vacuum with a household vacuum. See the section on escaped fibers below |
If you are not sure whether a specimen is asbestiform, treat it as if it is until a geologist or an accredited asbestos laboratory says otherwise. COG 2/11 points to the NIST National Voluntary Laboratory Accreditation Program list of accredited asbestos labs [2].
Storing an asbestiform specimen
- Bag it. COG 11/11 says asbestos minerals can be stored in a sealable, clearly marked bag to keep particles from becoming airborne [1]. Put the specimen in its box, then the box in the bag, so the bag is not punctured by sharp edges.
- Mark it. Write the species and "asbestiform: do not open or cut" on the bag and on the specimen label. The label fields are covered on what a label has to carry.
- Label the cabinet. COG 11/11 calls for the appropriate NFPA hazard warning symbol on cabinets that hold hazardous minerals [1].
- Do not open the bag to look. If you want to show the specimen, show it through the bag.
- Limit handling. COG 2/11 says to "Limit asbestos exposure to the shortest period possible" and, for contaminated material, to wear protective clothing, neoprene gloves and "a rated breathing apparatus with a HEPA filter" [2].
If fibers have escaped
COG 2/11 gives no cleanup method for a household. What it gives is a sampling method for museum staff: mist the area first with "a fine water mist, such as a plant mister," collect material into a lidded vial, seal the lid and wipe the outside with a damp cloth [2]. Its principle is to keep fibers wet and never disturb them dry. For loose fibers in a specimen box, the least disturbing course is to close the box, seal it unopened in a bag, mark it, and ask your state or local asbestos program what to do next. Do not use a broom, a brush, compressed air or an ordinary vacuum.
COG 2/11 is clear that contaminated collections or rooms are not a do-it-yourself job: it says to contact a conservator "equipped and trained" for asbestos work when collections have been contaminated [2]. If a drawer or a room has visible fiber contamination, call your state or local asbestos program or a licensed asbestos contractor before doing anything else.
Reasons to keep one, and reasons to let it go
There are good reasons to keep one: a well-labeled chrysotile from a historic mine is a legitimate part of a systematic or locality collection, and museums keep them. There are also good reasons to let one go: no one in the house wants it, the specimen is friable, or it came in an old collection with no data. If you sell it, buyers and platforms will need to know what it is, and carriers have rules for it (see the shipping page linked above). If you want to give it to a museum or university, call first and ask whether it accepts asbestos specimens at all; do not send or drop one off unasked.
Disposal: whose rules apply
EPA's asbestos air rule (the asbestos NESHAP) covers demolition and renovation and, as EPA describes it, excludes "residential buildings that have four or fewer dwelling units" [3]. EPA also notes that "state and local agencies may have more stringent standards than those required by the federal government" [3]. No federal source read for this page addresses a single mineral specimen. In practice that makes your state or local asbestos program, or your county's household hazardous waste program, the agency to ask. Do not put an asbestos specimen loose in household trash. The routes are set out on getting rid of hazardous specimens.
The next decision: keep, sell or dispose
Whichever way you go, the bag stays sealed. If the specimen is staying, the cabinet routine for hazardous minerals is on handling and storing toxic minerals. If it is leaving, go to getting rid of hazardous specimens or, for a sale, the shipping page.
References
- National Park Service, Conserve O Gram 11/11, *Health and Safety Issues with Geological Specimens*, Greg McDonald, September 2006. https://www.nps.gov/subjects/museums/upload/11-11_508.pdf
- National Park Service, Conserve O Gram 2/11, *Health and Safety Risks of Asbestos*, Diane Vogt-O'Connor, September 1999. https://nps.gov/subjects/museums/upload/02-11_508.pdf
- U.S. Environmental Protection Agency, *Information for Owners and Managers of Buildings that Contain Asbestos*, last updated July 2, 2026. https://www.epa.gov/asbestos/information-owners-and-managers-buildings-contain-asbestos
