How to store unsold stock so it stays sellable and documented
Updated
On this page8
Unsold stock stays sellable when three things stay true: it is kept apart from your own collection, every piece carries its label and source record, and it is stored in conditions that do not slowly destroy it. The conditions are the same ones museums manage: relative humidity (RH) kept below 60 percent, and above 35 percent where hydrated species are present, closed boxes for light-sensitive species, and storage materials that do not give off acids [1][2]. This page sets up a stock room that keeps those three things true, and tells you what to do when a piece goes off condition anyway.
Keep your collection and your stock in different places
The single habit that prevents most later trouble is physical separation. Your personal collection and your stock should live in different cabinets, different flats or at least different, clearly marked drawers, with separate catalog numbering. Two reasons make this worth the space.
The first is legal. BLM lets hobbyists collect "reasonable amounts" for "noncommercial purposes," and collecting for sale or barter "may be done only after obtaining a contract or permit from an authorized officer" [3]. Material you took under that personal-use allowance is not stock. If your own self-collected pieces sit in the same drawer as stock bought from a dealer, you lose the ability to show which is which. The short version is on collector or dealer; what counts as lawful stock and the records that prove it live on lawful stock.
The second is commercial. Stock needs a price, a cost and a date of acquisition; a collection piece needs none of those. When the two are mixed, pieces you meant to keep end up on a show table and pieces you meant to sell sit for years.
A simple numbering split does most of the work. One workable scheme gives stock its own prefix (for example S-2026-0141 for stock and a plain number for the collection), so a label read at a glance tells you which shelf the piece belongs on. Any prefix works if you use it everywhere.
What travels with every piece of stock
A specimen without its data is worth less, and stock without a source record is harder to sell lawfully. Conserve O Gram 11/2 is blunt about labels: "never throw away old labels" [1]. For stock, keep the label and the source record together, and keep a copy of the record in your books.
| Item | Where it lives | Why it matters |
|---|---|---|
| Specimen label (species, locality, size if you use size classes) | In the box with the piece | Buyers check the locality first; a lost label is close to a total loss of value |
| Old dealer or collection labels | In the box, in a small polyester sleeve if fragile [1] | Provenance; never discard them |
| Stock number | On the label and in the catalog | Ties the piece to its record |
| Source record (who you bought it from, or where and under what permission you collected it, with date) | In your catalog or stock spreadsheet; paper copy in a file | Shows the piece is lawful stock |
| Cost and date acquired | Catalog only | Pricing and taxes |
| Treatment, repair or condition notes | On the label and in the catalog | Disclosure at sale |
| Hazard note (toxic, asbestiform, radioactive) | On the box and the cabinet [2] | Your safety and the buyer's |
Conserve O Gram 11/2 also says "All boxes, cabinets and drawers need to be clearly labeled to prevent unnecessary disruption of specimens" [1]. In a stock room that means labeling the outside of each drawer with its stock number range, so you can pull an order without opening every drawer. How to lay out flats and drawers so any piece can be found is on flats and drawers, and the catalog fields are on keeping the catalog.
The conditions that ruin stock
Stock suffers from the same problems as a collection, with one difference: it often sits in cheaper boxes, in bulk, in a garage or storage unit, for longer than anyone intended. The table gives the short version of each problem and links to the page that covers it.
| Problem | Species most at risk | What the source says | Full explanation |
|---|---|---|---|
| Pyrite decay | Pyrite, marcasite and other iron sulfides | "Pyrite decay can be triggered by RH over 60 %" [1] | Pyrite decay |
| Deliquescence | Water-soluble minerals such as halite | RH "above 60%" can cause deliquescent minerals to dissolve [1] | Humidity |
| Dehydration cracking | Hydrated minerals | RH "below 35 %" may cause cracking "as minerals lose water" [1] | Dehydration |
| Acid attack and efflorescence | Calcite and other carbonates, shells | Wood, coatings, adhesives and sealants can release acids; in a sealed cabinet "these gases cannot escape" [2] | Acid vapors |
| Fading | Light-sensitive species | "Light sensitive mineral specimens should not be exhibited and should be stored in closed cabinets" [1] | Light fading |
| Crumbling foam and staining | Anything packed on polyurethane foam | Polyurethane foam can become brittle "after only a few months," turns yellowish brown, "could stain an object by contact and can emit corrosive acids" [4] | Cushioning |
| Breakage | Everything, worst in loose bulk lots | Shifting trays in drawers; COG 11/2 suggests space holders so trays do not move [1] | Breakage |
Two practical points follow from the table.
A garage or storage unit is the worst place for stock that includes sulfides, soluble species or hydrated minerals, because RH there follows the weather. If that is the space you have, keep those species indoors in sealed boxes and store only stable material (most quartz, agate, jasper and similar silica) in the unit. How to build a small sealed box for the vulnerable pieces is on sealed storage.
Wholesale packing is not storage. Flats of tumbled stones or clusters often arrive wrapped in newspaper, packed in polyurethane foam or bedded in shredded paper. Unpack them, check every piece, and rehouse anything you will hold for more than a few months. The Canadian Conservation Institute says low-cost polyurethane foam is acceptable for short-term use but "not suitable for long-term use" [4].
Stock that needs a shelf of its own
Some species are hazardous enough that they should be stored apart from other stock and labeled on the outside of the box and the cabinet. Conserve O Gram 11/11 tells museums to label cabinets holding such minerals with the appropriate National Fire Protection Association hazard symbol, and says asbestiform minerals "can be secondarily stored in a sealable bag in order to prevent individual particles from becoming airborne," with the contents "clearly marked on the bag" [2]. Conserve O Gram 11/2 says radioactive specimens "should be stored in polyethylene bags with zip closures" and that cinnabar may need "a vapor barrier envelope to reduce mercury vapor emission" [1].
That is a short version. Which species are on the list, and how to handle them, live on dangerous minerals and radioactive minerals at home. Shipping them is a separate question with its own rules, on shipping hazardous specimens.
When a piece goes off condition
You will find problems, usually at the annual check or when you pull a piece for a show. Decide what to do by what you see.
White powder or a sulfur smell on a sulfide
What it means: pyrite decay has started. It does not reverse. What to do: separate the piece at once so the acid products do not spread to its box mates and label. Do not sell it as sound. A piece with active decay can be offered only with the decay stated plainly, priced as damaged, or withdrawn. Withdrawing it is usually the better choice, because a buyer who opens a box of powder six months later remembers the seller.
White fuzz or crust on calcite or shells
What it means: likely efflorescence from acid vapors, often from a wooden drawer or cabinet [2]. What to do: move the piece out of the source and check its neighbors. The cleaning question and the identification of the salts are covered on efflorescence. Disclose any cleaning when you sell.
A crystal gone cloudy, chalky or cracked
What it means: dehydration, if the species is hydrated and the room has been dry [1]. What to do: it will not come back. Sell it described as it now is, or withdraw it.
Faded color
What it means: light exposure, usually from a display or a window. What to do: move the rest of that species into closed storage [1]. Price the faded piece on its current color, not its original one, and do not describe it from an old photo.
A broken or reattached crystal
What it means: handling or packing damage. What to do: repairs must be disclosed. How to word it on a label or listing is on disclosure, and how to look for old repairs is on repairs and restoration.
Disclose, mark down or withdraw
The rule of thumb that keeps your reputation is simple: the buyer should know what you know. Write the condition change on the label and in the catalog the day you find it, so the information is still there when the piece sells a year later. Trade custom for disclosure, and the wording dealers use ("as received," "repaired," "stabilized"), is explained on disclosure.
A stock-room routine that holds up
- On arrival, unpack, check against the invoice, photograph any damage, number every piece, and write or file the source record before the piece goes on a shelf.
- Rehouse anything packed on polyurethane foam or in loose newspaper if it will be stored for more than a few months [4].
- Sort by risk. Sulfides, soluble and hydrated species go in sealed boxes in the most stable room you have. Hazardous species go on their own labeled shelf [1][2].
- Label the outside of every drawer with its stock range [1].
- Log RH in the stock room through the seasons; the numbers to watch are on humidity.
- Check once a year and after every show, using the routine on the annual condition check.
- Record every change of condition, location or price in the catalog on the day it happens.
Turning sound stock into a price
Once stock is stored, labeled and documented, the next decision is what to ask for it. The method for specimens (realized comparables) and for decorative stock (pricing on cost) is on what to charge. The records that a growing business has to keep, including how long, are on what you have to write down.
References
- National Park Service, Kathy Hall, *Storage Concerns for Geological Collections*, Conserve O Gram 11/2, April 1998. https://www.nps.gov/subjects/museums/upload/11-02_508.pdf
- 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
- Legal Information Institute, 43 CFR 8365.1-5, Property and resources, current text read October 22, 2026. https://www.law.cornell.edu/cfr/text/43/8365.1-5
- Canadian Conservation Institute, Jean Tétreault, *Products Used in Preventive Conservation*, Technical Bulletin 32, issued February 7, 2018, modified February 19, 2021. https://www.canada.ca/en/conservation-institute/services/conservation-preservation-publications/technical-bulletins/products-used-preventive-conservation.html
