The killer test in the stack is Sigma PMA lot of folks here have been rotating profits into physical gold bars as a non-correlated hedge. Worth knowing the verification problem on the institutional side has gotten worse — Shenzhen-made 1mm tungsten-shell counterfeits hit US/EU wholesalers throughout 2024–2025.
The dealer SOP that catches them in <5 min per bar:
- XRF for surface composition
- Ultrasound for sub-surface echo (tungsten interior produces distinct signature)
- Density Archimedes ±0.01 g/cc
- Sigma PMV electromagnetic conductivity (gold 45.2 vs tungsten 18.9 MS/m — physically impossible to spoof)
- Caliper + LBMA serial check
If your dealer can't run at least 3 of these in front of you when you buy, find a different dealer. Full breakdown including a $475K/year ROI case study here:
https://www.wisermachine.com/bullion-dealer-incoming-gold-bar-xrf-verification-sop-2026/~5-min read, written for dealers but useful for any retail stacker buying $10K+ bars.
