Every bar we sell is genuine, and we guarantee it.

The first thing we do is put every bar and coin on a calibrated analytical balance. Investment-grade bullion sits in a narrow range just above its stated mass, because refiners always over-pour by a few milligrams to guarantee the stamped minimum.

Counterfeits almost always fail here. A genuine 1oz gold bar might weigh 31.108 g, while a tungsten-core fake of the same size reads several tenths of a gram out. That one test catches most of the counterfeits in circulation.

A small number of high-end fakes are weighted with tungsten, and they get past the density test because tungsten is almost exactly as dense as gold. Sound, though, travels through tungsten about 38% faster than through gold, and that is what ultrasound measures.

We pulse an ultrasonic probe against the bar and read the thickness back. A genuine 10oz gold bar about 8 mm thick reads about 8 mm. A tungsten-core fake of the same physical thickness reads closer to 5 mm, because the waves pass through it too quickly. The same test finds hollow cavities inside a bar.

An XRF spectrometer fires broad-spectrum X-rays at the bar. The metal re-emits X-rays at wavelengths unique to each element, and the detector reads those signatures into a full breakdown of what the bar is made of, in under 20 seconds and to 0.01% accuracy.

XRF reads only the surface, about 20 microns deep, so we never use it on its own. It is very good at catching gold-plated counterfeits, because the nickel and other alloys used in plating show up straight away. Put together with density and ultrasound, it closes the last gap.