A severely deformed 1834 British silver sixpence preserves physical evidence most consistent with an unusual minting anomaly, according to an IA STUDIO study published in npj Heritage Science.
The coin was individually marked £8 in a mixed coin album at a car boot sale in Greater Manchester. The album was later acquired as a job lot, rather than the sixpence being purchased separately for £8.
The study examined a William IV sixpence whose extraordinary deformation could not be confidently explained through visual examination alone. The investigation used scanning electron microscopy, chemical analysis and three-dimensional surface measurements to test competing explanations for the deformation.
The measurements revealed severe disruption concentrated in the central fields of the coin, while substantial portions of the rim and edge milling remained comparatively well preserved. Three-dimensional measurements identified steep-sided troughs, raised shoulders, terraced deformation and overlapping displacement structures. The damaged obverse region showed approximately 0.75 millimetres of vertical relief variation.
Taken together, the chemical, microscopic and topographic findings are most consistent with severe localised deformation involving repeated high-pressure loading under at least partial lateral constraint.
The study favours a mint-stage striking anomaly over ordinary wear, corrosion or a single unconstrained later impact.
Reading the evidence in the metal
The investigation combined scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDX) and optical surface profilometry.
SEM-EDX identified a silver-copper substrate in comparatively intact regions of the coin. Damaged areas showed lower measured silver levels, elevated copper and additional chemical signatures consistent with corrosion products and surface contamination concentrated within mechanically disturbed depressions.
These chemical findings primarily describe changes to the coin’s surface. Although corrosion and contamination are present, neither adequately explains the extent or geometry of the deformation.
Optical surface profilometry provided a detailed three-dimensional record of the damaged surface. It revealed abrupt changes in relief, steep-sided troughs, raised shoulders, terraced structures and overlapping displacement across the most severely affected areas.
The author analysed height-grid data supplied by the Oxford Materials Characterisation Service, identifying approximately 750 micrometres, or 0.75 millimetres, of vertical relief variation in the damaged central portrait region on the obverse.
The combination of substantial central displacement and comparatively preserved peripheral features is more compatible with repeated constrained compression than with the gradual smoothing associated with circulation wear or the loss of material through corrosion.
A material record of early mechanised minting
The sixpence was struck in 1834, during the steam-press era of British coinage.
Severe striking failures were ordinarily identified during mint inspection and remelted, particularly in the production of precious-metal coins. A surviving example may therefore preserve unusual physical evidence of a transient abnormal event within an early mechanised manufacturing process.
Distinguishing a manufacturing anomaly from subsequent damage can be particularly difficult when a historic metal object has undergone extensive deformation.
To address this, the study examined substrate composition, surface alteration and deformation geometry separately before bringing the findings together to evaluate competing explanations.
Beyond the individual coin, the research demonstrates a transferable, non-destructive approach to investigating metallic heritage objects whose unusual features cannot be confidently attributed to manufacture, use, corrosion or later damage through visual examination alone.
Hypotheses tested against physical evidence
Before laboratory measurements became available, the investigation began with high-resolution imagery and a structured visual review of the coin’s unusual features.
This initial examination helped establish several possible explanations for the deformation and identify the physical evidence needed to distinguish between them.
Human-supervised computational tools, including large language models (LLMs), were used to organise observations, structure alternative hypotheses, support comparative reasoning and develop questions that could subsequently be tested through laboratory analysis.
The working hypotheses and analytical notes were documented before the independent laboratory measurements were available.
The explanations considered included circulation wear and corrosion, later mechanical damage, later constrained compression and deformation during minting.
These possibilities were then evaluated against non-destructive measurements independently commissioned from the Experimental Techniques Centre at Brunel University of London and the Oxford Materials Characterisation Service, Department of Materials, University of Oxford.
Following laboratory testing, computational tools were also used to help organise the independently produced measurements and compare them with the earlier hypotheses.
“The important sequence was hypothesis first, independent laboratory measurement second,” said A. Ikraam, founder of IA STUDIO and author of the study.
“We used the models to ask what features mattered and what evidence could distinguish one explanation from another. Then the laboratory measurements gave us something physical to test those ideas against. The models could support the reasoning process, but they could not decide what happened to the coin.”
The computational tools did not generate the laboratory measurements or determine the study’s conclusion.
The independently produced laboratory datasets remained the primary scientific evidence, while responsibility for interpreting the results and reaching the final judgement rested with the author.
Analytical services
Non-destructive analytical services were independently commissioned from the Experimental Techniques Centre at Brunel University of London and the Oxford Materials Characterisation Service, Department of Materials, University of Oxford.
The involvement of these facilities does not imply institutional authorship or endorsement of the study’s interpretation, conclusions or computational methodology.
About IA STUDIO
IA STUDIO is an independent heritage science research initiative combining historical investigation, digital documentation, laboratory measurement, human expertise and supervised computational methods, including AI, to investigate difficult questions about material objects and their histories.
npj Heritage Science
Imaging analysis
Not applicable
Laboratory investigation of a deformed 1834 William IV sixpence
24-Sep-2026
The author declares no competing financial or non financial interests.