Scientific method
X-ray fluorescence
Also known as XRF
Measures the characteristic X-rays emitted by a sample under excitation, giving the concentrations of major and some minor elements. Strong on abundant elements, limited on the trace elements that carry most geochemical information.
Classification
- method class
- experimental
- access
- indirect
How this record is known
- 2
- Settled consensus
- Cited as the accepted position of the discipline.
- 1
- Interpretation
- Reached by reasoning from evidence, or produced by a named model.
3 of 3 claims on this page cite at least one registered source. Counts describe how each statement is known, not how likely it is to be true.
What Lithoen records
Each claim states how it is known and cites its evidence.
EstablishedIts sensitivity falls away at trace concentrations, which is where most geochemical information about process and source actually lives.
Precision degrades as concentration approaches the detection limit: the USGS method reports a relative standard deviation averaging 2.4 percent above 50 ppm, 7.5 percent below 50 ppm but above three times the lower limit of determination, and 18 percent below three times that limit. Interferences are spectral-line overlaps, matrix effects, spectral artifacts, and particle size or mineralogical effects.
- precision note: Recorded so that a result from this method is never read as more than the method can support.
Evidence support: Supported by the cited evidence · one source
Evidence: D.F. 2000 · Primary authority
EstablishedThe characteristic x-rays a sample emits when excited.
X-ray fluorescence records the characteristic X-ray photons a sample emits when bombarded by X-rays of a selected energy. In the USGS energy-dispersive method a powdered sample is pressed into a cup and analysed without being dissolved or destroyed.
- precision note: What the instrument records and what a geologist concludes from it are different statements; this claim is about the former.
Evidence support: Supported by the cited evidence · one source
Evidence: D.F. 2000 · Primary authority
InferredThe concentrations of major and some minor elements.
The USGS energy-dispersive X-ray fluorescence method determines thirty trace elements routinely, from vanadium through to uranium, as a qualitative and quantitative elemental analysis of liquid and solid samples.
- method: The inferential step from instrument reading to geological information.
Evidence support: Supported by the cited evidence · one source
Evidence: D.F. 2000 · Primary authority
Record last updated 2026-09-06. Corrections follow the published corrections policy; superseded claims are retained, never silently edited.