---
title: "Stones, clasps and the parts of a piece that are not metal"
description: "Stones, clasp springs, enamel, pearls, glass and watch movements: how each is spotted, how its weight is left out, and how to get your stones back."
canonical: "https://assaypost.co.uk/guides/stones-clasps-and-what-is-not-metal"
published: "2026-09-07"
modified: "2026-09-24"
language: "en-GB"
publisher: "Assaypost"
---

# Stones, clasps and the parts of a piece that are not metal

Written at the Assaypost bench, checked before publication. Published 7 September 2026. Updated 24 September 2026.

**The short answer:** Anything in a piece that is not precious metal is listed and its weight left out of the assessment: a stone, a clasp spring, enamel, glass, a brooch pin, a watch movement. Where a part cannot be weighed on its own, its weight is estimated and shown as an estimate. Nothing is taken apart to do it: under clause 4.4 of the terms, nothing is dismantled and no stone is taken out before you have accepted an offer. Assaypost does not buy gemstones, so a stone is never quietly absorbed into an offer; it is listed, and it stays in its setting unless you agree in writing to its removal (clause 4.2). The consequence people most often miss is that a stone worth more than the piece around it should not be in the parcel at all.

## Why the not-metal is left out rather than absorbed

The stone in a ring is usually the part its owner cares about most, and the part a metal buyer can do least with. Those two facts sit awkwardly together, and the only fair way to handle them is to take the piece apart on paper before anything is decided about it.

A refinery recovers gold, silver, platinum and palladium. It does not recover a garnet, a pearl, a steel spring or a watch movement, and every one of those has to come out before the metal is refined, which only happens after you have sold it. Leaving them in the description of a piece would mean describing the piece as something it is not.

Leaving a stone out of the weight says nothing at all about what it is worth. A diamond can be worth many times the ring it sits in, which is precisely why it is kept out of a metal transaction rather than folded into one. Telling you that, before you commit to anything, is the point of doing it in the open.

## What is not metal, where it hides, and how it is spotted

**Non-metal and base-metal parts commonly found on jewellery and silverware**

| Material | Where it hides | Why its weight is left out | How it is spotted |
| --- | --- | --- | --- |
| Gemstones and paste | Rings, pendants, earrings | Not metal, and often the better part | Eye and loupe |
| Steel springs | Box, lobster and bolt-ring clasps | Steel spoils a melt | A magnet pulls at the clasp only |
| Enamel | Badges, lockets, watch dials | Glass fused on; will not come off whole | Eye and loupe |
| Pearls, coral, jet, amber | Necklaces, brooches, mourning pieces | Organic, and often collected | Eye; weighed apart where loose |
| Cement, wax, plaster | Under old settings, inside hollow beads | Filler, and more of the weight than you would think | Weight against size |
| Glass | Lockets, scent bottles, watch crystals | Not metal | Eye; its weight estimated in place |
| Watch movements | Gold and silver watch cases | Steel and brass, and worth money to a repairer | Seen inside the case back; its weight estimated |
| Steel pins, brass findings | Brooches, cufflinks, repaired chains | Base metal | Magnet, then testing |

> **The magnet is doing more work than it looks**
>
> Gold and silver alloys are not drawn to a magnet. A pull at the clasp says there is a steel spring inside it. A pull along the whole chain says the chain is not gold at all. It takes two seconds, it costs nothing, and you can do it at your own kitchen table before you decide whether to send anything.

## What can be told from a photograph, and what has to wait for the bench

A good photograph settles more than people expect. It shows whether a ring is set or plain, whether a clasp is a box or a bolt ring, whether a locket has glass in it, whether a brooch pin is a different colour from the body. It does not show what is under a stone, and it never shows what is inside a hollow piece.

1. **Put something known in the frame**: A one-pound coin or a ruler beside the piece turns a guess about size into a measurement. Stone size is read from proportion, and proportion needs a reference.
2. **Photograph the underside as well as the top**: The back of a setting says whether a stone is foil-backed or open, whether a brooch has been repaired, and whether a locket opens. The top of a piece is the least informative view of it.
3. **Say what you already know**: A receipt, an old insurance valuation or a setting certificate that states a stone's weight replaces an estimate with a fact. If you have paperwork, say so before anything is posted.
4. **Then the bench does what a photograph cannot**: Each piece is weighed whole and examined as it is. Nothing is taken off it. A stone's size is read from its dimensions in the setting, and the weight of a spring, a pin or a movement is estimated from what it is. Each estimate is shown as one on the offer and left out of the assessment.
5. **Everything left out is written down**: Each part that is not metal is listed with what it is, what its weight was taken to be and how that was worked out, so the description of the piece matches the piece.

If what the bench finds differs from what the photographs suggested, you are told before anything else happens, with the reason. Nothing about a piece is revised quietly.

## Where a stone ends up, and how to make sure it comes back

Assaypost does not buy gemstones. Valuing gems is a different trade with a different market and a different set of qualifications, and pretending otherwise would be an easy way to short-change someone. That leaves three possible endings for a stone in a piece you are thinking of selling.

- **It comes back to you.** Ask for stones to be taken out and returned. A stone is removed only with your written agreement (clause 4.2 of the terms) and only once you have accepted the offer, where it can be unset without damage and the work is proportionate. Ask when you send your photographs, or when the offer arrives. Do not assume it.
- **It stays with the piece.** Where removal would damage the stone or you have not asked for it, the stone stays where it is and nothing is paid for it. It is still listed, so you can see it was there.
- **It goes somewhere else entirely.** If a stone may be worth more than its mount, the plain answer is that this is the wrong route for the piece. Take it to a jeweller, a gem laboratory or an auction house, or have the stone taken out locally and send only the mount.

> **Ask before, not after**
>
> The Office of Fair Trading's investigation into buying gold by post, which ran from 2009 to 2011, found a lack of clarity about whether gemstones were bought, returned or at risk of damage. The safeguard is simple and it is yours to use: agree in writing what will happen to your stones before anything is processed, and check that the itemised list names each stone and says where it went.

## What the sort looks like on the tray

It helps to picture it as a physical sort rather than a piece of arithmetic, because that is what it is. A parcel arrives, it is opened, and everything in it is laid out and photographed before a single piece is touched.

1. The hallmarked and marked pieces go together, because the marks can be read and recorded first.
2. The unmarked pieces go beside them, to be identified by test rather than by reading.
3. Anything with a stone in it goes on its own, because the decision about a stone is separate from the decision about the metal around it.
4. Coins, watches, signed pieces and anything that looks old enough to matter go into a group of their own, untouched, to be looked at properly rather than processed.
5. The plated and base-metal pieces go into a fifth group. They are listed and they come back; they are never quietly kept.
6. What is left, once the clasps have been checked with a magnet and the fillings found, is the metal. That is the part this business buys.

A canteen of cutlery sorts the same way. The forks and spoons are solid and go in whole. The knives go to one side, because a sterling handle is a hollow shell around pitch and a steel blade. A pair of candlesticks goes to one side too, for the reason the [weighted silver guide](https://assaypost.co.uk/guides/weighted-and-loaded-silver) explains.

Nothing in that sequence turns into a sum you could do at home, and it is not meant to. What it gives you is a list: this is what arrived, this is what each thing is, this is what in it is not metal and what weight was left out for it. One written offer for the lot follows, and you decide.

## Seller risks and exceptions

- A figure quoted on the whole weight of a stone-set piece will always look better than one given after the piece has been looked at properly. If any buyer gives you a number before they have seen what is in the setting, ask them what they assumed.
- Stones set in cement or with foil backs, common in Georgian and Victorian jewellery, can rarely be taken out intact. If you want such a stone back, say so before anything is processed and accept that it may not be possible.
- Small stones in pavé and channel settings are light one by one and numerous together. They are recorded as a group, so ask how the group was counted if it matters to you.
- Enamel and glass cannot be separated from metal without destroying the decoration. An enamelled piece with no collector interest is dealt with as metal with the enamel noted; one with collector interest should not be here at all.
- A watch movement is not metal and is not bought as metal, and it stays in its case until you have accepted an offer. Some movements are worth real money to a repairer or a collector, and the [gold watches page](https://assaypost.co.uk/what-we-buy/gold-watches) explains what happens to a movement and how to have it back.
- If what the bench finds differs from what your photographs suggested, the offer will differ too. You are told what changed and why, and you can decline and have everything back at no cost under the arrangements on the [offers, returns and payment](https://assaypost.co.uk/offers-returns-and-payment) page.

## When not to use this route at all

> **If the stone might be worth more than the mount, stop here**
>
> A diamond much above half a carat, a sapphire, ruby or emerald of good colour, a natural pearl, or any stone that came with a laboratory report is usually worth more than the metal around it, and sometimes many times more. This route pays nothing for a stone. Have the piece looked at by a jeweller or an auction house first, or have the stone taken out and send only the mount.

The same goes for signed pieces and antique settings, where the setting itself is the interesting part. The [what we buy](https://assaypost.co.uk/what-we-buy) pages list what triggers a second look for each material, and the [scrap gold jewellery page](https://assaypost.co.uk/what-we-buy/scrap-gold-jewellery) covers the everyday cases. The guide to [what is worth having looked at first](https://assaypost.co.uk/guides/what-to-have-looked-at-before-you-sell) is the one to read if you are not sure which of your pieces belongs in which pile.

## Questions sellers ask

### Do you buy the stones in my jewellery?

No. Assaypost buys precious metal, and valuing gems is a different trade. Stones are listed and their weight left out. They stay in their settings unless you agree in writing to their removal, and one you ask for back is taken out after you accept, where practical, and sent to you.

### How do you know how big a stone is without taking it out?

From its dimensions and its type, using standard gemmological tables that relate size and shape to weight. A round brilliant of about 6.5 mm across is roughly one carat, and a carat is 0.2 g. The figure is shown on the offer as an estimate, and no stone is taken out to check it before you have accepted.

### Will I get my stones back?

Only if you ask before the piece is processed and removal is practical, so ask early. Some stones, especially those set in cement or with foil backs, cannot come out intact. Agree the arrangement when you send your photographs or when the offer arrives, and check that it is written down.

### Why is the clasp on my chain treated separately?

Most box, lobster and bolt-ring clasps have a steel spring inside, and some clasps are base metal all through. A magnet finds them in a second. The gold part of a clasp is part of the chain; the spring and any base metal are not.

### What if I disagree with what was left out?

Ask. Every part left out of a piece's weight is written down with what it is and how its weight was established, and a person can talk you through it. If you are still not satisfied, decline and everything comes back free, as it arrived. Nothing is processed while a question is open.

## Sources

1. [GOV.UK — CMA case: purchase of gold by post, unfair contract terms](https://www.gov.uk/cma-cases/purchase-of-gold-by-post-unfair-contract-terms) (accessed 21 September 2026)
2. [GOV.UK — Hallmarking: how businesses can comply with the law](https://www.gov.uk/guidance/hallmarking-how-businesses-can-comply-with-the-law) (accessed 7 September 2026)

## Related

- [What to keep back: the pieces worth having looked at properly first](https://assaypost.co.uk/guides/what-to-have-looked-at-before-you-sell)
- [A box of jewellery you cannot identify: where to start](https://assaypost.co.uk/guides/a-box-of-jewellery-you-cannot-identify)
- [Scrap gold jewellery](https://assaypost.co.uk/what-we-buy/scrap-gold-jewellery)
- [Gold watches](https://assaypost.co.uk/what-we-buy/gold-watches)
- [Offers, returns and payment](https://assaypost.co.uk/offers-returns-and-payment)
- [Weighted and loaded silver: why candlesticks, trophies and knife handles weigh more than their silver](https://assaypost.co.uk/guides/weighted-and-loaded-silver)
- [Inherited jewellery](https://assaypost.co.uk/inherited-jewellery)

## Start with photographs

- [Send a photo on WhatsApp](https://wa.me/447369296063?text=Hello.%20I've%20been%20reading%20your%20guides%20and%20I've%20got%20some%20pieces%20I%20can't%20identify.%20Sending%20photos%20now.)
- [Request a prepaid label](https://assaypost.co.uk/postal-pack)
- Telephone [07369 296063](tel:07369296063), 6am to 10pm, seven days a week