Opal Doublet Thickness Check

Correct caller microscopy top/backing intercepts for oblique section geometry and audit top fraction; two-layer geometry does not identify opal, treatment or adhesive condition.

Description

An oblique section length exceeds the normal thickness of a flat layer.

An oblique section length exceeds the normal thickness of a flat layer. Multiplying top and backing intercepts by the appropriate cosine recovers an ideal two-layer thickness ledger.^[1]

Correct caller microscopy top/backing intercepts for oblique section geometry and audit top fraction; two-layer geometry does not identify opal, treatment or adhesive condition.

When to use Opal Doublet Thickness Check

Use this tool to correct caller microscopy top/backing intercepts for oblique section geometry and audit top fraction; two-layer geometry does not identify opal, treatment or adhesive condition.

Prepare the gemstone measurements, spectra or comparison data and any supplied calibration parameters. Check units, reference conditions and record alignment.

How to use Opal Doublet Thickness Check 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 observedTopBackingLayerInterceptsMm, sectionNormalToLayerAngleDegrees, callerMinimumTopLayerFraction using the field table and calculation rules, then run the tool.
Read normalTopBackingLayerThicknessesMm, topLayerFraction, belowCallerTopLayerCriterion. 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
observedTopBackingLayerInterceptsMm	Observed top backing layer intercepts mm	list of number	Required
sectionNormalToLayerAngleDegrees	Section normal to layer angle degrees	number	Required
callerMinimumTopLayerFraction	Caller minimum top layer fraction	number	Required

Enter exactly two nonnegative top/backing intercepts in mm, signed angle with absolute value below 90° and a minimum top fraction in [0,1]. Require positive corrected total, then return both normal thicknesses, top fraction and a strict below-criterion flag.

normal thickness=observed intercept × cos(section-normal angle)

Units, indexing, boundary conditions and exceptional cases are defined in the calculation rules above.

Output field	Meaning	Value type
normalTopBackingLayerThicknessesMm	Normal top backing layer thicknesses mm	list of number
topLayerFraction	Top layer fraction	number
belowCallerTopLayerCriterion	Below caller top layer criterion	boolean

json

{
  "input": {
    "observedTopBackingLayerInterceptsMm": [
      1,
      2
    ],
    "sectionNormalToLayerAngleDegrees": 60,
    "callerMinimumTopLayerFraction": 0.4
  },
  "output": {
    "normalTopBackingLayerThicknessesMm": [
      0.5000000000000001,
      1.0000000000000002
    ],
    "topLayerFraction": 0.3333333333333333,
    "belowCallerTopLayerCriterion": true
  }
}

Limitations and assumptions

Two-layer geometry does not identify opal, treatment or adhesive condition.

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 Pearl Nacre Thickness Estimate: Model minimum/maximum nacre thickness around eccentric spherical nucleus with exact nonoverlap shell volume; ideal measured geometry does not establish natural/cultured origin or actual uniform nacre quality. For a complementary task, use Total Depth Percentage: Audit measured total depth against independently measured crown/girdle/pavilion depth ledger and girdle diameter; closure error remains signed, not another solitary component-percentage alias.

References

Opal Doublet Thickness Check — tool.io

Similar or alternative tools

Pearl Nacre Thickness Estimate
Model minimum/maximum nacre thickness around eccentric spherical nucleus with exact nonoverlap shell volume; ideal measured geometry does not establish natural/cultured origin or actual uniform nacre quality.
Total Depth Percentage
Audit measured total depth against independently measured crown/girdle/pavilion depth ledger and girdle diameter; closure error remains signed, not another solitary component-percentage alias.