How has the composition of the Nobel medals changed over time and why was 18K adopted around 1980?
Executive summary
The Nobel medals were originally struck in high-purity gold (about 23-carat) from the first awards until 1980; since then they have been produced as 18‑carat “green” or electrum gold and finished with a thin layer of 24‑carat gold plating (often from recycled sources), a change documented by the Nobel Foundation and multiple reference sources [1] [2] [3] [4]. Reporting ties the shift to practical factors — material conservation, manufacturing and appearance considerations, and an explicit move toward recycled gold — but the Foundation’s public statements do not provide a single, detailed technical rationale that attributes the change to one overriding motive [4] [5].
1. The medal’s original composition: solid 23‑carat gold
From the institution of the prizes in the early 1900s through 1980, the Swedish “academic” medals (physics, chemistry, physiology/medicine, literature) and the Norwegian Peace Prize medals were made of roughly 23‑carat gold — a high‑purity formulation often described as about 96% gold — and these early medals are the ones cited in historical episodes such as the wartime dissolutions and postwar recastings [1] [2] [6].
2. The 1980 inflection: 18‑carat green gold with 24‑carat plating
Beginning in 1980, the official composition changed: medals have been struck in 18‑carat green gold (an alloy commonly called electrum, containing gold and silver, and sometimes described as recycled gold) and are then plated with 24‑carat gold to give the bright pure‑gold appearance laureates expect [2] [3] [7]. Multiple reference works and the Nobel organisations themselves describe this construction consistently, and some medal weights and dimensions were adjusted in the same era for specific categories [8] [2].
3. The Nobel Foundation’s stated practice: recycled gold
Contemporary descriptions from the Nobel organizations and major encyclopedias emphasize that post‑1980 medals are made from 18‑carat recycled gold, signaling an institutional policy toward reuse or sourcing of reclaimed precious metal rather than freshly mined bullion [4] [5]. That language appears in recent mainstream reporting and reference material and frames the shift as partly ethical or practical procurement policy rather than purely aesthetic [4] [5].
4. Practical drivers suggested in secondary reporting: durability, appearance, cost and fabrication
Secondary sources and specialists point to sensible manufacturing reasons for the change: 18‑carat alloys are harder and less prone to damage during striking and handling than near‑pure 23‑carat gold, and plating with 24‑carat gold preserves a lustrous finish while economizing on the quantity of pure gold needed; these rationales appear across explanatory pieces about the medals [6] [7] [9]. Reports also note that electrum (green gold) contains silver which changes mechanical properties, and that plating helps maintain the traditional “pure gold” external look without using solid high‑karat material [3] [6].
5. What remains uncertain or unreported: the single decisive motive
None of the provided sources contain a definitive official memorandum from the Nobel Foundation laying out a single decisive motive — such as explicit cost‑cutting, legal restrictions on gold export, or anti‑theft policy — for the 1980 shift, so attribution beyond the Foundation’s recycled‑gold statement requires inference from manufacturing practice and later press accounts [4] [2]. Alternative explanations exist in public discourse — including cost moderation, supply chain changes, conservation/ethical sourcing, and easier manufacture — but the primary sources supplied do not prioritize these reasons in a single authoritative declaration [4] [5] [7].
6. Reading between the lines and the agendas of sources
Institutional sources (Nobel organizations, Britannica) emphasize recycled gold and continuity of appearance, which aligns with reputational and ethical agendas to appear responsible stewards of a symbolic national treasure, while auction and refiners’ commentary often foregrounds melt value and material composition for commercial interest; both perspectives are present in the coverage and should be weighed accordingly [4] [5] [9]. Where precise motivations matter — for example, whether the change was driven chiefly by ethics, economics, or metallurgy — the reporting indicates plausible drivers but stops short of a single, explicit origin story in the public record [4] [6].