Selling an Inherited Fossil, Mineral or Meteorite Collection

Most inherited natural history collections arrive in the same way: drawers of fossils, boxes of minerals, perhaps a few pieces said to be meteorites, and handwritten labels nobody in the family can quite read.

The instinct is to clear them quickly. It is usually the wrong one. What makes a collection like this valuable is often not the specimens alone but the information that came with them, and that information is easily lost in the first week.

This note sets out what to do before anything is sold. It is general guidance, not tax or legal advice, and an executor with a sizeable estate should take professional advice on the tax points.

Keep everything together

Before anything is moved, cleaned or divided, keep each specimen with whatever is with it.

That means labels, numbers painted or written on the specimen, the trays and boxes they sit in, notebooks, catalogues, letters, receipts and photographs. A label giving a locality, a date and a collector’s name can turn an ordinary-looking specimen into a documented one, and once a label is separated from its specimen the connection usually cannot be rebuilt.

The Natural History Museum records exactly these details for its own specimens: the label, a unique number, the identification, and the locality, collector and date where they are known. Its interest in them is the best guide to why they matter.

Do not wash, glue or “tidy” specimens. Cleaning can remove material that matters, and some old specimens are fragile in ways that are not obvious.

Be careful with what you handle

Most old collections are entirely safe. A few contain material that needs care.

The Natural Sciences Collections Association, the UK body for natural science collections, has published guidance on identifying radioactive geological specimens. Uranium-bearing minerals were popular with collectors, and they were often kept alongside everything else. Asbestos minerals and some arsenic- and mercury-bearing minerals turn up too.

Our practice is simple: if a box is labelled with a uranium mineral, or contains specimens you cannot identify, leave it closed in a ventilated space and tell whoever assesses the collection. Do not grind, break or scrape anything to see what it is.

Valuation for probate

If the estate is being valued for Inheritance Tax, a collection counts among the household and personal goods.

GOV.UK lists antiques and collections among the items an estate must include, and the figure HMRC asks for is open market value: the price the item might reasonably be expected to fetch if sold on the open market at the date of death. HMRC’s own manual notes that insurance or replacement values can overstate this, and that it will usually accept a professional valuation prepared on an open-market basis.

Collections are entered on form IHT407, which has a separate place for antiques, works of art and collections and asks for a copy of any professional valuation. GOV.UK suggests a professional valuation for anything worth more than £1,500.

Two practical points follow. First, a sale soon after death is strong evidence of value, so the figure achieved matters to the estate as well as to the family. Second, a valuer needs to see the labels and documents, not just the specimens, because they are part of what is being valued.

Capital Gains Tax when you sell

Selling an inherited item can raise a Capital Gains Tax question, though often it does not.

For personal possessions, GOV.UK states that no Capital Gains Tax is due on an item sold for £6,000 or less. Above that, a marginal relief limits the taxable gain, and items forming a set sold to the same person or connected people are treated as one item. For an inherited item the starting point is its value at the date of death, which is usually the probate figure.

So a sound probate valuation does two jobs: it settles the Inheritance Tax position and fixes the baseline for any later gain. Executors and beneficiaries with significant specimens should confirm their position with an accountant.

Museums and the nation

Some families would like part of a collection to go to a museum. That is possible, but it works best when it is planned.

The Natural History Museum may accept donations of material that fits its collecting priorities and was legally obtained. It asks what the material is, where and when it was collected and how the donor came to own it, and it asks people not to send specimens without a curator agreeing first.

For objects of real importance there is also Acceptance in Lieu, administered by Arts Council England. It allows an Inheritance Tax bill to be paid by transferring pre-eminent cultural, scientific or historic objects to the nation. It applies to a small number of exceptional pieces, not to most collections, but it is worth knowing it exists.

Meteorites need particular care

Pieces described as meteorites deserve a sceptical eye.

A genuine meteorite with an official name has been classified, and its name approved by the Meteoritical Society’s Nomenclature Committee and published in the Meteoritical Bulletin. A specimen labelled with a recognised name can be checked against the Bulletin’s database.

A “meteorite” with no name and no paperwork may be one, or may be slag, magnetite or iron-rich rock, which are often mistaken for meteorites. Our view is that it should be treated as unidentified until someone qualified has examined it. Our note on meteorite provenance explains what a documented specimen looks like.

Fossils and the question of title

Fossils collected long ago and kept in a family collection are normally the family’s to sell, but buyers increasingly ask how they were obtained.

The position varies across the UK. In Scotland, NatureScot’s Scottish Fossil Code notes that fossils belong to the owner of the mineral rights, and that selling a fossil needs full legal title from that owner. Material taken from protected sites raises its own questions. Old notes on where and when specimens were collected help to answer them, which is another reason to keep every scrap of paper.

Selling well

There are three routes, and each suits a different collection.

An outright sale is quickest and most certain, and the figure reflects that. Consignment usually achieves more for good material, because specimens are researched, photographed and offered to buyers who are looking for them. Auction gives reach and a fixed date, at the cost of fees on both sides and less control over the description.

Whichever route you choose, ask the buyer or agent how they will describe the specimens, what they will do with the labels and documents, and whether the collection will be kept together where that matters to its value.

We take inherited natural history collections on consignment and will also give a straightforward view of whether they would do better elsewhere. If you are unsure what you have, send us photographs, including the labels. The first conversation costs nothing.

For how we judge individual pieces, see our notes on fossil quality and mineral specimens.