Most executors who sit down with a jewellery box and a blank IHT407 are making a perfectly reasonable decision. A modest estate with a few gold chains, a dress ring and a drawer of costume pieces does not need a paid valuation, and HMRC does not expect one. The form asks for a professional valuation to be enclosed if you have one, not for one to be obtained.

The problems arise in the middle ground: the box that contains one or two pieces of real substance among twenty that have none, and the executor who has no reliable way of telling which is which. The mistakes below are the ones we see repeatedly. Two of them push the figure up, two push it down, and one does whichever it feels like. None is a failure of diligence. They are failures of information.

What HMRC Is Actually Asking For

Probate valuation means open market value at the date of death, which is not what the piece cost, not what it would cost to replace, and not what it is worth to the family. Section 160 of the Inheritance Tax Act 1984 sets the test as the price the property might “reasonably be expected to fetch if sold in the open market” at that time, which for jewellery means the auction room or the second-hand trade rather than the shop window.

Any single item worth £1,500 or more has to be listed individually on form IHT407 rather than disappearing into the aggregate figure for household goods. And the error runs in both directions: too low, and the estate is exposed to a penalty for a careless inaccuracy; too high, and it pays tax on money it never had.

1. Using the Insurance Figure

An insurance valuation answers a different question, which is what it would cost to walk into a shop and replace the piece, new, today, complete with the jeweller’s margin, the VAT and the premium for matching something at short notice. None of that survives into open market value, and on mass-market diamond jewellery the difference is a multiple rather than a margin. A ring insured for £6,000 can have a probate value nearer £1,200.

Older documents compound the problem. Many were index-linked, the sum insured lifted by a fixed percentage every year for two or three decades regardless of what the market underneath it was doing, and since diamond prices have not tracked retail inflation over the past ten years, a 1995 figure uplifted annually ever since has drifted a long way from anything real. Valuers also once charged a percentage of the sum insured, which gave them an obvious interest in a generous number. That practice has largely gone. The paperwork it produced is still in the drawer, and it is usually the first thing an executor reaches for.

An old schedule is useful evidence of what existed and roughly what it was. It says nothing reliable about what it is worth.

2. Pricing at Today’s Gold Price

The valuation date is the date of death, but estates are commonly settled six or nine months later, and in a year like this one that gap does real damage. Gold in sterling reached roughly £128 a gram for fine metal in the first quarter of 2026 and had fallen to about £95 by the middle of July, close to a quarter of the value gone in a matter of months. The LBMA benchmark price is the reference point, and the figure you want is the one published for the day the owner died.

On a 4g 9ct wedding band that is the difference between about £190 and about £140, which sounds trivial until it is applied across a box of chains, bracelets and odd earrings. An executor pricing a January death at July’s rates understates the estate. One pricing a July death against the spring peak hands HMRC tax on value that had already evaporated. The same discipline applies to everything else in the estate that moves with the market, cars and motorbikes included.

3. Trusting an Old Valuation to Say What Is in the Box

A schedule from 1978 describes 1978. In the decades since, pieces have been sold, lost, broken up, remounted, upgraded on anniversaries and repaired with whatever the trade had that week, and stones are replaced after damage rather more often than anyone admits. None of it reaches the paperwork, and executors still work down the list matching ring to ring against descriptions written for a different set of objects.

Identification is the other half of the problem, and it is where amateur confidence tends to outrun amateur capability. Synthetic rubies and sapphires were going into commercial jewellery before the First World War, spinel and garnet stood in for ruby long before that, and diamond simulants have improved with every decade: paste, then cubic zirconia, then moissanite. Laboratory-grown diamonds are now diamond in every physical and optical respect and can be separated only with instruments, which makes a naked-eye judgement about any diamond ring made in the past fifteen years worth very little.

4. Weighing the Metal and Missing the Maker

Silver makes the point most economically. A brooch of twenty grams is worth a few tens of pounds melted, but signed by Georg Jensen, to a design by Henning Koppel, Vivianna Torun or Arno Malinowski, it can be worth four figures, and a matched necklace or suite more again. Nothing about the object declares itself to someone who is not looking for it.

Period jewellery is the other blind spot, and Georgian work suffers worst because it does not look like modern jewellery: closed backs, foiled stones, low-carat gold gone dull with age, flat-cut garnets that read as dark glass under a kitchen light. Pieces like these are routinely tipped into the costume tray, and whatever damage they carry is taken as confirmation. Condition counts for far less in early jewellery than in modern, and a good Georgian garnet necklace with knocks in it remains a serious piece of jewellery.

Watches deserve the same suspicion and are better assessed on their own terms than swept in with the jewellery.

5. Valuing the Memory

The wedding band she wore every day for fifty years, the one everybody in the family can picture, is four grams of gold to the market. The instinct to price it higher is a decent one, and sentiment is the point of most jewellery, but it produces a figure that cannot be evidenced to anyone who asks for the reasoning behind it.

The reverse causes more trouble. Where a piece is going to a beneficiary rather than to auction, executors sometimes reason that a modest figure is harmless because nothing is being sold, when the item goes on the form at open market value whether it is sold, kept or handed over. The IHT407 also asks what any sold items fetched, and where something has gone for less than market value, HMRC still expects the full open market figure to be returned.

When to Do It Yourself, and When Not To

Costume jewellery, plain low-carat gold and anything unsigned that is obviously well under £1,500 can be handled at the kitchen table with auction archives and an hour of patience, as can most of the rest of a house contents valuation.

The pieces that warrant a second opinion are the ones that might cross £1,500, anything signed, anything that looks older than the twentieth century, anything with coloured stones and any watch of substance. That is where the gap between what an executor sees and what the object actually is runs into thousands of pounds, in either direction, and where a wrong figure is least likely to pass unnoticed.

The aim is not the lowest number or the highest one. It is a number that can be stood behind when somebody asks, which is usually also the one that leaves the estate paying the right amount of tax and no more.

If a piece is giving you pause, our jewellery probate valuations establish open market value at the date of death, in writing, for submission with the IHT407.