---
title: "Mangled 1834 William IV sixpence from a car-boot sale; lab scans point to a failure inside the mint"
url: https://badiyaa.com/william-iv-sixpence-1834-mint-error/
published: 2026-11-12T11:51:00+00:00
modified: 2026-11-12T11:51:00+00:00
section: Science
publisher: Badiyaa
---

# Mangled 1834 William IV sixpence from a car-boot sale; lab scans point to a failure inside the mint

A crushed 1834 William IV sixpence from a Greater Manchester car-boot sale was most likely deformed at the mint during striking, a lab study finds.

A silver sixpence struck in 1834 and later crushed almost beyond recognition was most likely ruined inside the mint as it was being made, not damaged in the 192 years since, according to a laboratory study in [npj Heritage Science](https://doi.org/10.1038/s40494-026-02901-0). Across its battered center, the coin’s surface rises and falls by as much as about 750 micrometers, three-quarters of a millimeter on a coin barely 19 millimeters wide.

The coin turned up in a mixed album bought at a car-boot sale, Britain’s version of a flea market run from the trunks of cars, in Greater Manchester, England. Its finder, A. Ikraam, a self-funded heritage researcher who runs IA STUDIO in London, wanted to know when and how it got its strange shape.

## A coin that should not exist

Sixpences of William IV carry a simple reverse: the words SIX PENCE under a crown, with the date below and a wreath around them, according to the [history of the British sixpence](https://en.wikipedia.org/wiki/Sixpence_(British_coin)). On this specimen the denomination is almost wiped out, while much of the rim and the milled edge survive.

That combination is the puzzle. The paper notes that badly failed strikes were normally caught at inspection and melted down, especially in precious-metal coinage, so a survivor is unusual. Early opinions based on photos favored damage after the coin left the mint, and a specialist who handled it in person also rejected the mint explanation, Ikraam wrote in a post about the project.

## How the coin was tested

Ikraam paid two outside labs to do the measuring. Brunel University London’s Experimental Techniques Centre examined the surface with a scanning electron microscope that also reads the chemical elements present. The University of Oxford’s materials characterization service mapped the coin’s height in fine detail with optical profilometry.

The chemistry came back as expected for old British silver. Comparatively intact spots were dominated by silver with a little copper, roughly 88 to 97 percent silver by weight, close to the sterling standard of 92.5 percent used for sixpences from 1816. The damaged pockets told a different story, with silver as low as about 25 percent and traces of carbon, silicon, aluminum, iron, calcium, sulfur and chlorine. The study reads those as grime and corrosion lodged in the dents, not as the cause of them.

The height maps carried the argument. They show stepped terraces, steep-sided troughs, raised shoulders and overlapping squeeze marks, with an average roughness near 67 micrometers in the damaged zone. Ordinary wear would smooth the high points evenly, corrosion alone could not shove metal around that far, and a single later blow would be expected to leave a simpler crater. Repeated pressing while the coin was held in from the sides fits better, the paper concludes, the kind of confinement found during striking.

For scale, 750 micrometers is about the thickness of seven or eight sheets of standard 0.1-millimeter printer paper stacked together, pushed into and out of a coin that weighed just 2.83 grams.

## Where AI fit in

The study openly used AI tools under the author’s supervision to organize observations and weigh competing explanations. Both the paper and Ikraam’s post stress that the tools produced no measurements and did not decide the conclusion. “A scientific interpretation is not strengthened by claiming more than the evidence can support,” Ikraam wrote.

## Limits

This is one coin examined by one author. There was no cross-sectioning, bulk assay or record of the striking itself, and the raw lab data are not public. The paper says a later squeeze under confinement cannot be ruled out absolutely, so the result narrows the options rather than reconstructing every step.

Scans have been settling old questions lately: CT imaging recently cracked the [four-letter code of a padlock from a 1583 Welsh shipwreck](https://badiyaa.com/ann-francis-shipwreck-padlock-code-ance/), and a treasure hunt in Georgia turned up [an 1861 Mexican silver coin](https://badiyaa.com/josh-gates-confederate-gold-1861-silver-coin/). The mangled sixpence was worth half a shilling, one-fortieth of a pound, when it left the press in 1834.

## Further reading

- [npj Heritage Science: Laboratory investigation of a deformed 1834 William IV sixpence](https://doi.org/10.1038/s40494-026-02901-0)

- [Wikipedia: Sixpence (British coin)](https://en.wikipedia.org/wiki/Sixpence_(British_coin))

*Image: The Portable Antiquities Scheme, Frank Basford, CC BY-SA 4.0 via Wikimedia Commons*

*This article was produced with AI assistance and reviewed by our Editorial Desk. [How we work](https://badiyaa.com/editorial-policy/).*