Single Reading Refractometer Estimate
Calibrate a single curved-surface spot reading against caller instrument references with propagated reading bounds/extrapolation flag; not a definitive RI, full principal indices or identity lookup.
Description
A refractometer spot reading can be calibrated against independent reference indices.
A refractometer spot reading can be calibrated against independent reference indices. Propagating reading uncertainty gives compatible index bounds rather than a single definitive identity.1
Calibrate a single curved-surface spot reading against caller instrument references with propagated reading bounds/extrapolation flag; not a definitive RI, full principal indices or identity lookup.
When to use Single Reading Refractometer Estimate
Use this tool to calibrate a single curved-surface spot reading against caller instrument references with propagated reading bounds/extrapolation flag; not a definitive RI, full principal indices or identity lookup.
Prepare the gemstone measurements, spectra or comparison data and any supplied calibration parameters. Check units, reference conditions and record alignment.
How to use Single Reading Refractometer Estimate and understand its results
- Prepare the gemstone measurements, spectra or comparison data and any supplied calibration parameters. Check units, reference conditions and record alignment.
- Enter referenceSpotReadings, referenceIndices, sampleSpotReading, spotReadingHalfUncertainty using the field table and calculation rules, then run the tool.
- Read calibratedSampleRi, calibratedSampleRiBounds, sampleOutsideSpotCalibration. The explanation below defines the units, signs, ordering and any flags or placeholder values.
- If the tool reports an input issue, correct the values and run it again. Apply the stated assumptions when interpreting a successfully returned result.
| Input field | Meaning | Value type; see rules below | Requirement |
|---|---|---|---|
| referenceSpotReadings | Reference spot readings | list of number | Required |
| referenceIndices | Reference indices | list of number | Required |
| sampleSpotReading | Sample spot reading | number | Required |
| spotReadingHalfUncertainty | Spot reading half uncertainty | number | Required |
Pair strictly increasing reference spot readings with positive indices and at least two samples. Fit a positive-slope linear model, evaluate the sample and its ±nonnegative uncertainty endpoints, requiring positive predicted indices. Flag any uncertainty endpoint strictly outside calibration coverage.
Each sequence checked for increasing order must contain at least two strictly increasing values. The least-squares fit needs at least two aligned observations and a varying independent variable; a constant dependent variable has reported R² of 1.
calibrated RI=fitted intercept+positive slope × spot reading Units, indexing, boundary conditions and exceptional cases are defined in the calculation rules above.
| Output field | Meaning | Value type |
|---|---|---|
| calibratedSampleRi | Calibrated sample ri | number |
| calibratedSampleRiBounds | Calibrated sample ri bounds | list of number |
| sampleOutsideSpotCalibration | Sample outside spot calibration | boolean |
{
"input": {
"referenceSpotReadings": [
1,
2
],
"referenceIndices": [
1.5,
2
],
"sampleSpotReading": 1.5,
"spotReadingHalfUncertainty": 0.1
},
"output": {
"calibratedSampleRi": 1.75,
"calibratedSampleRiBounds": [
1.7,
1.8
],
"sampleOutsideSpotCalibration": false
}
}Limitations and assumptions
Extrapolation is flagged but allowed. Calibration uncertainty beyond reading bounds and full principal indices are not resolved.
Numeric inputs and returned numeric values must be finite; an unrepresentable returned value produces an error. Numeric lists are limited to 100,000 entries; the rules above may require smaller limits. Missing required fields, extra fields, wrong value types and violations of the calculation rules are input errors. A successfully returned false flag is an evaluated outcome; its meaning is explained above.
Alternative or Complementary methods
Use Refractive Index Snell: Infer optical index from independent measured refracted rays and incident-medium index; no mineral identity, normal-incidence division or ocean-wave speed/refraction alias. For a complementary task, use Birefringence Delta RI: Audit observed directional RI spread against caller resolution, not an inferred complete principal-index birefringence or mineral diagnostic; unobserved directions may hide larger spread.
References
-
Single Reading Refractometer Estimate — tool.io
Similar or alternative tools
- Refractive Index Snell
Infer optical index from independent measured refracted rays and incident-medium index; no mineral identity, normal-incidence division or ocean-wave speed/refraction alias.
- Birefringence Delta RI
Audit observed directional RI spread against caller resolution, not an inferred complete principal-index birefringence or mineral diagnostic; unobserved directions may hide larger spread.