Internal Continuity
Assess whether returning signals are consistent with the expected internal path through a suitable solid bar.
Gold Authentication Method
Ultrasonic Gold Bar Testing
Non-Destructive Internal Examination of Suitable Bullion
Ultrasonic testing introduces sound waves into a suitable solid bar and analyses returning signals for information about internal continuity.
It is an authentication and internal-integrity examination—not an assay for exact gold fineness.
Bilex confirms whether the item geometry, surface and available reference conditions make ultrasonic examination appropriate.
Bilex Sample Handling
What Ultrasonic Examination Can Show
An ultrasonic probe sends sound into a suitable solid item and receives reflected signals. Reflections may indicate the far surface, internal boundaries, discontinuities, voids or foreign inclusions that affect sound propagation.
The method preserves the bar and can add evidence about internal structure that a surface-composition measurement cannot provide. It should be interpreted alongside the item geometry, casting characteristics, calibration and other relevant examination results.
Ultrasonic examination does not determine exact gold fineness. An apparently consistent response does not by itself establish the analytical gold content of a bar, and the method must not be promoted as a guarantee against every counterfeit construction.
Applications
Where Ultrasonic Gold Bar Testing Is Used
Discontinuities
Identify reflections that may be associated with boundaries, voids or inclusions requiring review.
Large Cast Bars
Examine suitable cast bullion where geometry and surface condition support ultrasonic coupling.
Complementary Evidence
Combine internal-structure information with surface, physical or analytical evidence as appropriate.
Suitable material
Materials and Sample Forms
- Suitable cast gold bars
- Large bullion bars
- Selected solid doré bars where appropriate
- Other suitable solid items with workable geometry and surfaces
Before testing
Sample Requirements
- The item must be a suitable solid form; ore, powder, concentrate and loose nugget parcels are not appropriate for bar ultrasound.
- Geometry, accessible surfaces, coupling, calibration and reference conditions affect whether useful signals can be obtained.
- Casting porosity or legitimate metallurgical features can create responses that require careful interpretation rather than automatic rejection.
- Bilex confirms equipment availability, operator scope and reporting terminology before arranging the examination.
Process
From Testing Question to Report
Identify the Item
Record the bar or solid item and the internal-integrity question to be examined.
Review Suitability
Assess geometry, surfaces and reference conditions before confirming the test.
Set the Examination
Use appropriate equipment and calibration for the agreed scan approach.
Collect Responses
Introduce sound and record returning signals from the selected examination areas.
Interpret & Report
Review the responses with stated limitations and recommend complementary testing where justified.
What it contributes
Strengths
- Non-destructive internal examination
- Can indicate boundaries, discontinuities, voids or inclusions
- Adds evidence that surface-only methods cannot provide
- Suitable results can be retained for review and comparison
Scope
Limitations to Understand
- Does not determine exact fineness
- Does not guarantee detection of every counterfeit or anomaly
- Requires suitable geometry, surfaces, equipment and calibration
- Legitimate casting features can affect responses
- Not applicable to loose, powdered or granular material
Method selection
How This Method Relates to Other Tests
Ultrasound and XRF
XRF examines elemental composition in selected surface regions. Ultrasound examines how sound travels through the internal structure of a suitable solid bar.
They provide different evidence and may be complementary, but neither alone establishes representative bulk fineness of a thick bar.
Ultrasound and Fire Assay
Ultrasound preserves the item and examines internal integrity. Fire Assay determines gold from an appropriate representative analytical portion and consumes that portion.
If exact fineness is the question, ultrasonic consistency should not be substituted for an appropriate analytical determination.
Questions
Frequently Asked Questions
Does ultrasound determine gold purity?
No. It provides internal structural information and does not determine exact gold fineness.
Can ultrasound detect material inside a gold bar?
Reflections can indicate internal boundaries, voids or foreign inclusions, but interpretation depends on equipment, calibration, geometry and legitimate casting features.
Is ultrasonic testing destructive?
The examination is normally non-destructive for a suitable item and does not require removing an analytical portion.
Can ultrasound replace Fire Assay?
No. Ultrasound examines internal structure; Fire Assay determines gold in a representative prepared analytical portion.
Why might ultrasound and XRF be used together?
XRF adds surface elemental information while ultrasound adds internal structural evidence. Together they answer more than either examination alone, but they do not automatically establish bulk fineness.
Related services
Compare Supporting Methods
Discuss the sample
Book Ultrasonic Testing
Tell us the material, available sample quantity and the information the result needs to establish.
The final method and sample requirements are confirmed after the material and testing objective have been reviewed.