Guides
The parts a calculator cannot tell you
Three short pieces, written for somebody about to sell something and unsure whether they are about to be taken advantage of.
The most expensive misunderstanding in the trade, and the one every calculator on the internet quietly encourages.
5 min read
The chain from your kitchen drawer to the refinery, who takes what along the way, and why the same chain gets four different prices.
6 min read
What a stamp does and does not prove, and the checks you can do at home without damaging anything.
5 min read
Two terms that sound like the same idea and are legally a mile apart — the exact US minimums for each, and why one survives decades of wear and the other does not.
5 min read
A specific, legally defined term with three requirements — and why the sterling silver underneath, not the gold on top, is what actually holds resale value.
4 min read
A genuine mark can still be a forgery. The three ways UK law defines hallmark fraud, and the physical tells each one leaves behind.
6 min read
Both look the same colour on day one. What they are actually made of, why one needs replating and the other never does, and how they wear over decades.
6 min read
Carbon against silicon carbide: the measurable differences in hardness, fire and refraction, and why a thermal diamond tester alone cannot always tell them apart.
6 min read
Carat, cut, color and clarity are four independent measurements, not a single score — what each one actually grades, in the GIA’s own terms.
6 min read
Which common jewellery metals actually contain nickel, which structurally cannot, and why "nickel-free" is not a regulated claim in the US.
6 min read
Tarnish is silver sulfide grown out of the metal itself, so every cleaning takes some silver with it. Why museums put the effort into storage instead.
5 min read
The metal, the stones and the design decide it. How resizing is done at the bench, what rules it out, and the alternatives when it cannot be done.
5 min read
Melted, assayed and refined back to bullion: the Miller and Wohlwill processes, what fire assay measures, and the bar the whole chain ends in.
5 min read
One lends against your jewellery, the other buys it. Two different businesses, two different numbers, and what UK law says about getting a pawn back.
5 min read
Melt value, resale value and the figure an estate uses are three different numbers. How to sort and measure a collection first, and what each one means.
6 min read
One measures a gemstone’s weight, the other a gold alloy’s purity. Where each came from, what each number means exactly, and how to read them on a tag.
5 min read
A foreign stamp is a claim made under foreign rules, and the customs allowance at home is set by weight or value. What to measure, what to keep, and what to declare.
6 min read
A grading report describes a diamond; it does not value it. What each part of a report records, how a Dossier differs, and how to check a report is the stone’s.
6 min read
Most white gold is plated with rhodium, and the yellow that shows with wear is the alloy underneath. What rhodium is, and what US rules say about disclosing it.
5 min read
A tin alloy, not a precious metal. What the word legally claims in the US, what it cannot tell you about an old piece, and why this site gives it no figure.
5 min read
Three compulsory marks, a handful of optional ones, and an offence built on description. What a UK hallmark guarantees, who strikes it, and what is exempt.
6 min read
Under US rules, yes: the definition is about what the stone is, not where it formed. What the FTC requires a seller to disclose, and the words it restricts.
5 min read
A cultured pearl is grown by a mollusk around a nucleus a person put there. What US rules let the word “pearl” mean, and the words that must stand in front of it.
5 min read
The six-character code on an Indian gold hallmark, unique to each piece. The three marks BIS requires, the purity grades it lists, and what a HUID check confirms.
5 min read
A UK silver standard finer than sterling, at 958.4 parts per thousand. What the 958 mark and the seated Britannia figure mean, and where the standard came from in 1697.
5 min read
Sterling is silver all the way through; plate is a coating over another metal. What US and UK rules let each word mean, and what EPNS and nickel silver stand for.
6 min read
925 parts per thousand pure silver: the sterling standard. What the stamp promises in the US, the UK and India, how far short it may lawfully fall, and what it does not tell you.
6 min read
Silver with a gold-plated surface. How UK assay offices hallmark it as silver, the descriptions they allow and refuse, and how it differs from US vermeil.
5 min read
How a UK assay office marks a piece made of two precious metals, or of precious and base metal: which full hallmark is struck, where the second number goes, and what +METAL means.
6 min read
Mother-of-pearl is nacre from the inside of a shell, not a pearl. What gemmologists mean by it, how US rules define a pearl, and why the term needs care on imitation pearls.
5 min read
Since September 2025, hallmarked Indian silver carries a six-character HUID. The three-part mark, the seven grades, what BIS Care shows, and what the code cannot tell you.
5 min read
In US law, coin silver is at least 900 parts per thousand pure. How it sits beside sterling, how far a coin mark may fall short, and how the UK and India treat 900.
5 min read
999 is 99.9% pure silver. How a UK hallmark, an Indian BIS mark and a US stamp each treat it, the Britannia that can stand for it, and the tolerance on a US mark.
5 min read
The UK rule is about words. What Schedule 1 of the Hallmarking Act lets a trader say about unhallmarked jewellery, from “plated” and colour words to the exempt articles.
6 min read