How to buy an old mineral collection fairly

Buy a collection fairly by confirming the seller has the right to sell it, seeing all of it before you price any of it, keeping every label with its specimen, and making an offer you can explain piece by piece. Old collections often hold fossils, artifacts, and toxic, asbestiform or radioactive specimens, which change what you can resell and how you must handle them. One collector writing on Mindat in 2009 warned sellers that dealers may offer "anywhere from 1% (I kid you not) to 50%+" [1], so an offer you can explain stands out. This page covers the first visit, the sort, the offer, the authority to sell, and the material to separate.

Before you go: the seller's authority to sell

The person showing you the collection is not always the person entitled to sell it. Ask, and note the answer.

Who has authority over an estate is a matter of state law and the court's appointment. If anything about the seller's authority is unclear, wait until it is settled, and get a bill of sale signed by the right person. This is general information; an estate attorney can answer for a specific case.

The first visit

The first visit sets the tone of the deal and is the best chance to keep the collection's information intact.

1. See everything. Every cabinet, drawer, box and garage shelf. Value in a collection is uneven; one reader's comment on a Mindat article for sellers notes that "top pieces will always sell easilly and are like cash in the bank" [1].
2. Do not move labels. Photograph each drawer as you open it, labels in place, before anything is lifted.
3. Look for the paperwork. Catalogs, notebooks, dealer invoices and correspondence. The Mindat article tells sellers that "dealer labels can be extremely important and add some value to the collection itself" [1]; the same is true for buyers.
4. Note the hazards. Flag anything that may be radioactive, asbestiform or toxic for separate handling (see below).
5. Leave with a plan, not a price. Tell the seller when you will make an offer and how you will reach it.

Sorting and valuing

Sort before you price. A workable order:

• Labeled, with locality: the core of the value.
• Labeled but questionable: wrong species, impossible locality, label clearly not with its specimen. How to handle these is on when the label is wrong.
• No data: priced as material, not as specimens; see a specimen with no data.
• Restricted material: fossils, artifacts, meteorites (next section).
• Hazardous material: handled and priced separately, or excluded.

For each piece worth listing, do what the Mindat article asks sellers to do: photograph from several angles and "measure in 3 directions and to measure in Centimetres!" [1]. Then price from realized sales, not asking prices. The same article tells sellers to "Check finished auctions on Ebay and other auction websites" [1]. The method, with a worked example, is on what to charge, and the heir's side of the same question is on what a mineral collection is worth.

Making an offer you can explain

The Mindat article's range, from 1 percent to over 50 percent, describes what dealers offer sellers, as one writer saw it in 2009 [1]. It is one practitioner's observation, and its value is in showing how wide the gap between fair and unfair offers can be.

A fair offer is one you can show your working for:

• Estimate resale value for the pieces you will sell individually, from realized comparables.
• Subtract your real costs: cleaning, rehousing, cataloging, photography, fees, shipping, unsold stock and your time. These differ widely by business, so use your own numbers.
• Price bulk and no-data material as material.
• State what you are not buying (hazardous or restricted pieces) and why.
• Put the offer in writing, with the method.

Do not cherry-pick. The Mindat article advises sellers "do not let a dealer or buyer come by and 'Cherry' pick the specimens out of the collection" [1], because taking the best pieces leaves the rest hard to sell. If you only want part of a collection, say so up front and price the part honestly, knowing that the seller may prefer a buyer for the whole. As the article's author says, "Not all dealers are out to squeeze you, but some are" [1]. Be the first kind.

Fossils, artifacts and meteorites in old collections

Older collections often include fossils, arrowheads and meteorites, and these carry rules that ordinary minerals do not.

• Artifacts. BLM says cultural materials on its land may not be removed without a permit, including "arrowheads and other stone tools, grinding stones, beads, baskets, pottery" [2]. The Archaeological Resources Protection Act makes it a crime to sell, buy or transport archaeological resources removed from public or Indian lands in violation of federal law [3]. Its surface-arrowhead provisions take surface arrowheads out of ARPA's own criminal and civil penalties [3][6], but agency rules still forbid removing them [2]. Points with no record of where they were found cannot be shown to be lawful. The full rules are on arrowheads and other artifacts.
• Fossils. Casually collected fossils from federal land may not be bartered or sold [2]; fossils from private land with permission may be. Without records you may not know which you have; see can you sell fossils?.
• Meteorites. BLM's 2012 instruction memorandum on meteorites (IM 2012-182) allowed casual collection for personal use only, with no sale. The memorandum states that it expired on 09/30/2013, and BLM has published no replacement as of October 2026, so get the field office's answer in writing. The terms are on meteorites on public land.

Ask the seller what they know about where these came from, write it down, and leave out of your purchase anything you could not lawfully resell.

Hazardous specimens to separate first

Old collections were assembled before current handling advice, and hazardous species are often stored with everything else.

COG 11/11 also warns that when a sealed cabinet "is first opened" a person is exposed to whatever has built up inside [5]. Open old cabinets slowly, in a ventilated room, and step back before you start pulling drawers.

If you do not want hazardous specimens, say so in the offer and let the seller arrange their disposal or donation. How to get rid of them properly is on getting rid of hazardous specimens.

After the purchase

Get a bill of sale that lists the collection (by catalog numbers if it has them), the price, the date and the seller's name and authority. Keep it with the collection's records: it is the source record that makes every piece lawful stock in your hands. What that record must show, and how to carry it forward to your own buyers, is on what makes stock lawful. Keep every old label with its specimen as you rehouse; why they matter is on provenance and old labels.

References

1. Bri Dragonne, *Advice for people selling and sorting a mineral collection*, Mindat.org article 836, last updated November 19, 2009 (with reader comments). https://www.mindat.org/article.php/836/Advice+for+people+selling+and+sorting+a+mineral+collection.
2. Bureau of Land Management, *Can I Keep This? A guide to collecting on public lands*, BLM/MT/GI-11/007, revised 2021. https://www.blm.gov/sites/default/files/docs/2021-10/Can%20I%20Keep%20This%202021%20-%20508%20Final%20Version.pdf
3. Archaeological Resources Protection Act, 16 U.S.C. 470ee, via OpenJurist, read October 2026. https://openjurist.org/16/usc/470-ee
4. National Park Service, Conserve O Gram 11/10, *Radioactive Minerals*, Greg McDonald, September 2006. https://nps.gov/subjects/museums/upload/11-10_508.pdf
5. 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
6. Civil penalties, Archaeological Resources Protection Act, 16 U.S.C. 470ff, GovInfo, read October 22, 2026. https://www.govinfo.gov/link/uscode/16/470ff