Written by the house, offered freely.
A handful of quick checks will separate an obvious fake from a likely diamond. None of them is conclusive on its own — here is what each test really shows, and where it falls short.
A laboratory-grown diamond is a real diamond — not a simulant. The difference lies not in the crystal but in its origin, its price, and how it holds value over time.
An instrument reading a photograph is dependable about some things and structurally incapable of others. Here is the line between the two, and what the figure it returns is actually good for.
There is no single number. A diamond carries three at once, and which one you are owed depends entirely on what you are about to do with it.
Colour is graded on a stone lying face-down in a laboratory, and worn face-up on a hand. Those are two different questions, and only one of them is on the report.
Nearly every ring carries its own short description, struck a millimetre high inside the band. Most of it is one number, and the number is the part that cannot be dressed up.
A synthetic ruby is a real ruby. A glass-filled one is mostly ruby. A red glass bead is neither. Sorting those three apart is most of gemmology, and some of it you can do at a kitchen table.
Nobody designs a ring by choosing everything at once. A jeweller asks in a particular order, because each answer narrows the next — and the house has just made an instrument that asks the same nine questions and draws the ring as you answer them.
The one instrument that reads nothing has a different kind of limit. Its geometry is honest, its price is indicative, and no jeweller can make a ring from a picture.
A free app, a jeweller's tester, an independent appraiser and a laboratory report answer four different questions. Buying the wrong one is the commonest way people waste money on a stone.
Value in art is rarely about beauty. It follows a handful of factors — and one of them matters far more than the rest.
Identifying a painting is detective work. The answer is rarely in one place — it is assembled from the signature, the reverse, the materials and the style.
The hammer price is not the proceeds and the gallery price is not the payment. What a painting earns you depends nearly as much on the channel as on the picture.
He painted it from the window of an asylum, thought little of it, and never saw a penny of what it is now worth. The gap between what a work is and what it fetches is the most useful thing an owner can understand.
Munch made the same image at least five times, in different media, and two of them have been stolen. Everything anyone wants to know about the value of The Scream turns on which one they mean.
It was filthy, unattributed, and went for about the price of a meal. Nothing about the object changed afterwards. Only what was known about it — which is where value actually lives.
It is not set at night, it is not the size Rembrandt painted it, and the missing pieces have never been found. Three facts that between them explain most of what condition does to a painting's worth.
Thousands of them were printed and thousands more have been copied since. The image is identical in every one. Everything that decides the price is in the object.
The front of a painting is the part that lies. Turn it over: the stretcher, the weave, the nails and the labels are a dated document, and almost nobody looks at them.
Reliable on a museum wall, useful at an estate sale, and close to helpless on an unsigned picture from an attic. The difference is not the software — it is whether the painting was ever published.
One of the four routes costs nothing and is staffed by people whose job is to want your painting. Most people go to it last.
A watch tells you what it is in five places, and most people read only one of them. Here is the order to read them in, and how far a single photograph will take you before anything has to be opened.
The expensive decisions are made in the first week, usually by somebody trying to be helpful. This is the order that keeps the value in the watch.
A reference number says what a watch is. Only the serial, the hallmark or the manufacturer's archive says when — and on a watch that has been serviced for fifty years, those three can disagree.
The front of a watch gives you a name. The price lives on a number engraved between the lugs, and no photograph of the dial can reach it.
Every check that matters on a watch happens inside the case. That is why the conclusive route is a watchmaker with a case opener, and why nothing looking at the outside can finish the job.
A listing that reads “Speedy 30, monogram canvas, made in France, 2014” contains four separate identifications. Here is how each one is made, in the order that works.
The aisle gives you two minutes, bad light and nothing to compare against. That is enough, if you check things in the right order — and the right order is not the one most guides use.
A handful of bags from a handful of houses genuinely keep their money. Almost everything else loses most of it the moment the receipt is folded — and the difference is not the price tag.
Recognising a bag and authenticating one are two different jobs. An app does the first well, and the second not at all — because the parts that photograph best are the parts that get copied best.
A paid authentication is sensible on a four-figure bag and absurd on a ninety-pound one. The free step is working out which of those you are holding.
