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Assay identification and geology

A quantitative chemical analysis performed to determine the concentration of a specific element or mineral in a rock, ore, or soil sample. Fire assay is the traditional method for precious metals gold, silver, platinum , involving fusion with a lead-based flux, cupellation, and gravimetric measurement. Modern assay methods include atomic absorption spectroscopy AAS , inductively coupled plasma ICP analysis, and X-ray fluorescence XRF . Field: economic geology. Example: Drill core assay results from the Detour Lake gold deposit in Ontario returned intervals grading 1.02 g/t Au over 30 meters, confirming the economic potential of the ore body.. Related terms: Ore grade, Fire assay, Geochemical analysis, Cut-off grade.

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Sources, scope & corrections

These authoritative resources support category-level nomenclature, terminology, identification methods, and safety. When a specimen-specific safety warning appears, the public-health source listed here directly supports that precaution. They are not line-by-line citations for every other property on this entry, and natural specimens vary.

Editorial owner
GeoMiner
Last updated
2026-03-30T15:19:41.970235+00:00
Review status
Published; not independently peer-reviewed
  • USGS Thesaurus — U.S. Geological Survey. Controlled earth-science terminology used to describe USGS information resources.
  • Glossary of Geologic Terms — U.S. National Park Service. Geologic definitions prepared by the NPS Geologic Resources Inventory.

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Common questions

What does Assay mean in geology?
A quantitative chemical analysis performed to determine the concentration of a specific element or mineral in a rock, ore, or soil sample. Fire assay is the traditional method for precious metals gold, silver, platinum , involving fusion with a lead-based flux, cupellation, and gravimetric measurement. Modern assay methods include atomic absorption spectroscopy AAS , inductively coupled plasma ICP analysis, and X-ray fluorescence XRF .
What is an example of Assay?
Drill core assay results from the Detour Lake gold deposit in Ontario returned intervals grading 1.02 g/t Au over 30 meters, confirming the economic potential of the ore body.
Which earth-science field uses the term Assay?
Assay is used in economic geology.
Which terms are related to Assay?
Related terms in this reference are Ore grade, Fire assay, Geochemical analysis, Cut-off grade.

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