Delivering faster, safer, and more accurate gold analysis, Chrysos PhotonAssay™ is an environmentally-friendly replacement for fire assay on-site and in the laboratory.

Hitting samples with high-energy X-rays, PhotonAssay™ causes excitation of atomic nuclei allowing enhanced analysis of gold, silver, copper and other elements in as little as two minutes.

The Physics of Chrysos PhotonAssay™

Understand the science driving PhotonAssay’s success across the industry.

PhotonAssay™ Technical Features

  • True bulk measurement of large samples, typically 400–650 g
  • Minimal sample preparation e.g. crush to 2–3 mm top-size
  • Non-destructive; no chemical reagents required
  • Rapid (< 2 mins per sample, 70 samples/hour)
  • Excellent sensitivity (0.01 ppm detection limit on reagent blanks, 0.015-0.030 on typical gold ores)
  • Independent of sample matrix, chemistry or mineralogy
  • Fully-automated

PhotonAssay™ versus Fire Assay

  • Fire Assay


  • Time per sample
    Fire Assay ~3–4 hours
    PhotonAssay™ ~2 minutes
  • Sample size
    Fire Assay 10–50 grams
    PhotonAssay™ 400–650 grams
  • CO₂ per sample
    Fire Assay 0.91 kg
    PhotonAssay™ 0.455 kg
  • Hazardous waste per sample
    Fire Assay 0.31 kg
    PhotonAssay™ 0 kg
  • Energy use per sample
    Fire Assay ~1.3 kWh
    PhotonAssay™ ~0.65 kWh
  • Automation
    Fire Assay

Through rapid turnaround on high sample volumes, PhotonAssay™ provides timely quantitative data, drives optimisation through the value chain, and delivers the operational outcomes that matter to miners and laboratories.


  • Higher volume, lower cost
  • Increased market share
  • Unique, fully automated labs
  • Reduced human error
  • Enhanced QA/QC


  • Enhanced QA/QC
  • Optimised gold recovery
  • Reduced gold lost to dumps and tailings
  • Improved reliability and accuracy
  • Higher margins

Download the latest PhotonAssay™ presentation

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