Verifying that metal is what it claims to be involves several methods with different reliability.
Hallmarking
Official marks certifying purity in several jurisdictions.
Which is a legal requirement in some markets.
Assay
Destructive testing giving definitive results.
Which is impractical for finished products.
Non-destructive methods
Density, conductivity and spectroscopy.
Which vary in what they can detect.
Sophisticated counterfeits
Tungsten-cored bars matching density.
Which prompted ultrasound and other testing.
Why counterfeiting became a real problem
Tungsten has a density close to gold, which defeats the traditional weight and dimension check that served for centuries.
Which prompted the industry to adopt ultrasound, conductivity and spectroscopic testing.
Reputable dealers test what they buy, which is one of the practical reasons for buying and selling through established channels rather than privately.
Assay certificates
Documentation accompanying bars from recognised refiners.
Which supports resale.
Recognised refiners
Lists maintained by industry bodies.
Which dealers reference.
Chain of custody
Metal remaining in professional storage.
Which avoids reassay on sale.
Buying safely
Established dealers, recognised products and documentation retained.
Why this sector attracts so much bad information
Precious metals sit at the intersection of a genuine asset class, a physical product with wide retail margins, and a set of narratives about currency collapse and financial crisis that sell extremely well.
That combination produces an unusual amount of marketing dressed as analysis. The metal itself is a legitimate holding with a long history; a great deal of what is written about it is produced by people selling it, and the two are difficult to separate if you are reading only the material that finds you.
The questions worth asking before buying anything
What is the premium over spot, what will a dealer pay to buy it back, what exactly do I own if this is a storage or digital product, who holds it, is it allocated to me specifically, and what happens if the provider fails.
Those six questions dispose of most of the problems in this sector. They are all answerable before purchase, and a seller who cannot answer them clearly has told you something useful.
What the evidence actually supports
Low correlation with equities over long periods, which is a diversification argument. Not a reliable short-run inflation hedge, despite the reputation. Not a consistent crisis performer, despite the narrative. No income, so returns depend entirely on price.
That is a defensible case for a modest allocation and a much weaker case than the marketing makes, and the difference between the two is where most retail disappointment originates.
A general note
Nothing here is investment advice. Tax treatment, regulation, consumer protection and dealer practice differ substantially between countries. Anything with money attached warrants checking against the rules where you are and, for anything significant, advice from a qualified professional.
The gap between spot and reality
Almost everything that goes wrong for retail buyers in this sector comes down to one thing: the distance between the price quoted on a screen and the price at which an individual can actually buy and then sell.
That gap is made up of fabrication cost, distribution, dealer margin, sales tax where it applies, storage where it is needed, and the spread when selling back. None of it is hidden, all of it is checkable in advance, and almost nobody checks it before buying.
Where the reliable information is
Industry councils publish quarterly demand and supply data, free. Exchanges and benchmark administrators publish prices and methodology. Regulators publish warnings about specific firms and practices. Refiner accreditation lists are maintained publicly.
All of that is dry, none of it is promoted, and it is the material that actually describes the market rather than the material that is trying to sell you part of it.
A closing observation
Gold has been held as a store of value for a very long time and there are reasonable arguments for a modest allocation. Those arguments do not require any claims about currency collapse, and the material that leans on such claims is generally selling something at a premium.
Separating the asset from the narrative around it is most of what a buyer in this sector needs to do.
Further reading
Industry bodies publish demand, supply and price data quarterly and free. Financial regulators publish warnings about firms and practices in this sector, which are worth checking before dealing with anyone unfamiliar.
Both are considerably more useful than the commentary that dominates search results on these subjects, and neither has anything to sell.
One last practical point
Before buying physical metal, get a buyback quote from the dealer for the exact product you are considering. That single question tells you the round trip cost immediately.
A dealer who will not quote one, or whose buyback is far below spot, has answered a different and equally useful question.
A final caveat
Market structures, tax treatment and consumer protection in this sector differ substantially between countries and change. Anything with money attached is worth checking against the rules where you actually are.