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3 results for “Cut-off grade” in Science
Science · 10 August 2026
Where Gold Actually Comes From
…strial ore, and the binding constraint is the cost of retrieving mass from orbit, not the grade. · Start with a fact that sounds like a metaphor and is not: no process available to an ordinary star can make gold. Stellar fusion is profitable up to iron and then stops being profit…
Tomas Herrera · 18 min read
Science · 8 August 2026
The Metal That Went Medical
…idise on the shelf, will not leach reactive ions into a biological sample, and will not degrade under the light it is being read by — and the material earns its price. Reproducibility is worth more than raw cost in a diagnostic supply chain. · Beyond the strip · Immunogold labell…
Amara Okonjo · 15 min read
Science · 9 August 2026
The Metallurgy of Karat
…loy — and the design is where the engineering lives. · Karat is a fraction, not a quality grade: 24 parts by mass, so 18k is 75.0% gold and 9k is 37.5%. · Pure gold measures roughly 25 HV on the Vickers scale — softer than a fingernail can dent — which is why it is alloyed before…
Tomas Herrera · 16 min read
