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26 results for “surface plasmon resonance”
Science · 8 August 2026
The Metal That Went Medical
…you had a virus. · Gold nanoparticles are red because collective electron oscillations — surface plasmons — absorb green light at around 520 nanometres. · The colour is size-dependent and aggregation-sensitive, which is what makes the particles usable as a readout rather than ju…
Amara Okonjo · 19 min read
Craft · 22 July 2026
Hallmarks and Assay: How Anyone Proves Gold Is Gold
…Fire assay remains the referee method; XRF is fast and non-destructive but reads only the surface. · Karat and fineness describe the same thing on different scales: 18ct is 750 parts per thousand gold. · Plating, filling and surface enrichment are the failure modes that surface-r…
Yusuf Demir · 15 min read
Industry · 7 August 2026
How Fake Gold Is Detected
…s. · XRF is fast, non-destructive and reads only the outer tens of microns — it validates surface composition, never the interior. · Ultrasonic velocity testing is the standard front-line defence against core-filled bars, because sound travels through tungsten far faster than thr…
Tomas Herrera · 16 min read
Craft · 5 June 2026
The Alchemy of Craft: What Goldsmiths Know That Machines Don't
…old's chemical inertness, not just its softness, is what makes it uniquely suited to fine surface work and permanent colouring effects. · Recycled gold now dominates workshop supply in many trading centres, changing how goldsmiths think about metal provenance. · What does 18k gol…
Yusuf Demir · 16 min read
Industry · 4 August 2026
The Gold Inside Your Phone
…nding on the model and generation, spread across connector plating, printed-circuit-board surface finish, and the fine wires or bumps connecting silicon dies to their packages. At typical prices that is a few dollars of metal — negligible per unit, substantial across a billion un…
Tomas Herrera · 18 min read
Industry · 6 August 2026
The Scrap Trade
…gold; specialist refiners buying in volume pay far closer to it. · Handheld XRF reads the surface only, which is why plated and filled items are caught by density checks, file tests or a destructive assay. · Recycled gold is chemically identical to mined gold after refining — the…
Ingrid Sørensen · 16 min read
Science · 9 August 2026
The Metallurgy of Karat
…ngle piece. It will be about fire scale, the dark copper-oxide layer that forms under the surface of copper-rich alloys during soldering and only reveals itself halfway through the final polish. · These are the properties that determine whether a design can be executed at all, an…
Tomas Herrera · 17 min read
Mining · 19 August 2026
Nine Grams a Tonne
…ise waste rock and tailings, treat any residual water contamination, and rehabilitate the surface, funded by a closure bond posted before mining even begins. In practice, closure costs are frequently underestimated at the planning stage, and several major historical mine closures…
Amara Okonjo · 18 min read
Industry · 2 July 2026
Nine Nines: Inside a Modern Gold Refinery
…ire assay, XRF and ICP spectrometry differ in practice? XRF gives a fast, non-destructive surface reading used mainly for in-process monitoring; ICP spectrometry dissolves a sample to quantify trace impurities down to parts per million; fire assay is slower and manual but remains…
Tomas Herrera · 19 min read
Industry · 7 August 2026
After the Cyanide
…shape. Reagent circuits are rinsed and neutralised before the plant is stripped. Tailings surfaces are capped to exclude oxygen and shed water, or kept saturated to achieve the same end from the opposite direction, because both starve the sulphide oxidation reaction of what it ne…
Tomas Herrera · 16 min read
Mining · 22 May 2026
The Other Supply Chain: Artisanal Mining and the Mercury Problem
…out, usually by hand with hammers and chisels in the smallest operations, dragged to the surface, and then crushed — traditionally by hand with heavy stones or increasingly with small diesel-powered stamp mills — before any separation can begin. This is dramatically more labour-…
Amara Okonjo · 15 min read
Science · 10 August 2026
Where Gold Actually Comes From
…uch gold is in the Earth's core? Enough, by most estimates, to plate the entire planetary surface several metres deep — and utterly inaccessible. Gold is siderophile, meaning it dissolves preferentially into molten iron, so during core formation it followed the iron downwards and…
Tomas Herrera · 17 min read
Markets · 20 June 2026
Bring It Home: Central Banks and the Great Gold Repatriation
…ive payment systems and bilateral currency arrangements, but one in which gold repeatedly surfaces as a proposed common reference or settlement asset precisely because it is acceptable to parties who trust neither each other's currencies nor a third country's. · None of these pro…
Ingrid Sørensen · 14 min read
Mining · 5 August 2026
Grade, Cut-off and the Arithmetic of an Open Pit
…its life-of-mine average, because there is simply less overlying waste to remove near the surface. Cash costs in these early years look excellent, margins are strong, and the operation is, on paper, one of the better assets in its peer group. · By year eight, the pit has deepened…
Amara Okonjo · 20 min read
History · 9 August 2026
The Hoard Problem: What Buried Gold Actually Tells Us
…in the trade of unprovenanced antiquities more broadly, is a laundering pattern: objects surface with vague or fabricated collecting histories, pass through several hands and jurisdictions, and arrive at auction with a provenance that begins conveniently in the mid-twentieth cen…
Marguerite Adler · 16 min read
Industry · 20 August 2026
The Refiner's Ledger
…h-yellow, cast in a simple mould at or near a mine site thousands of kilometres away, its surface uneven, its exact composition genuinely unknown until it is assayed. It might be sixty per cent gold or it might be ninety, mixed with silver and a residue of base metals that varies…
Tomas Herrera · 17 min read
Markets · 8 August 2026
Moving Bullion: The Logistics Nobody Prices
Between the vault and the buyer sits an industry of armoured vehicles, sealed cargo, bonded warehouses and insurance clauses. It rarely makes news, and it is the reason a spot price in London can dive…
Ingrid Sørensen · 15 min read
Markets · 17 August 2026
Paper Gold: What You Own When You Do Not Own Bars
Most of the world's gold exposure is a contract, not a metal. Futures, unallocated accounts and exchange-traded funds each promise gold in a different way — and the differences only become visible whe…
Ingrid Sørensen · 23 min read
History · 14 July 2026
The Gold Standard: How a Soft Yellow Metal Became Money
For roughly five thousand years, humanity kept returning to the same element to settle its debts. The story is less about greed than about the unusually boring chemistry of atomic number 79. · Gold's…
Marguerite Adler · 14 min read
Markets · 11 September 2026
The Last Audit: What We Actually Know About the World's Official Gold
Governments report holding roughly 36,000 tonnes of gold — a figure quoted everywhere and verified almost nowhere. Between the published number and the physical bar sits a chain of certificates, custo…
Ingrid Sørensen · 22 min read
Markets · 8 September 2026
The Real-Rate Trade: Why Gold Moves When Bond Yields Do
For two decades the gold price could be read off an inflation-linked bond screen. Then, somewhere after 2022, the relationship stopped behaving — and the argument about why has become the most consequ…
Ingrid Sørensen · 25 min read
Markets · 18 August 2026
The Vault Beneath the City
Beneath the Bank of England and beneath lower Manhattan sit two of the largest concentrations of monetary gold on earth, moved between anonymous compartments by a handful of porters who never touch th…
Ingrid Sørensen · 22 min read
Craft · 3 August 2026
The Wedding-Season Bid: How Jewellery Demand Sets the Floor
Half the world's gold is worn, not stored. In India and China that distinction barely exists — and the buying behaviour it produces is the most reliably contrarian force in the entire market. · Jewell…
Yusuf Demir · 15 min read
Industry · 28 July 2026
Urban Mining: The Richest Gold Ore on Earth Is in Your Old Phone
A tonne of good underground ore holds a few grams of gold. A tonne of discarded circuit boards can hold two hundred. So why is most of it still going into landfill? · Concentration, not tonnage, is wh…
Tomas Herrera · 16 min read
Markets · 2 August 2026
Who Actually Sets the Gold Price
There is no single gold price. There is a London settlement number, a New York futures curve, a Shanghai premium and a jeweller's counter in Dubai — and the distance between them is where the market l…
Ingrid Sørensen · 16 min read
Markets · 6 August 2026
Why Central Banks Started Buying Gold Again
For three decades official institutions were net sellers of bullion, and the policy consensus treated the metal as a museum piece. Then, quietly, the world's reserve managers reversed. The reasons are…
Ingrid Sørensen · 14 min read
