Accurately determine gold purity. Quickly rule out counterfeit or gold-plated items. Both are critically important business requirements for pawn shops and jewelry retailers. This presentation discusses methods for precious metal and gold testing, with an emphasis on x-ray fluorescence (XRF).

1. The world leader in serving science
Nov. 10, 2015
Precious Metals Testing – with Portable XRF

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Today’s Presenters
Jonathan Margalit
Market Development Manager
Thermo Fisher Scientific
Seth Gold
Vice President
American Jewelry & Loan

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Webinar Overview
• Introduction and Fun Facts
• Precious Metal Jewelry
• Gold Testing Methods
• Thermo ScientificTM NitonTM AuDITOR
• Conclusions and Q&A

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We Are The World Leader in Serving Science
Premier Brands
• 50,000 employees in 50 countries
• $17 billion in annual revenues
• Unparalleled commercial reach
Unmatched Depth
• Leading innovative technologies
• Applications expertise
• Lab productivity partner
Global Scale

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Goldfinger Was Wrong!
• The world’s largest
stockpile of gold is NOT
in Fort Knox.
• It’s in the NY Federal
Reserve, holding 25% of
the world's reserve.

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Thinner Than a Human Hair
The visor of an astronaut’s space helmet receives 0.00005 millimeters
gold coating -- that’s 500 times thinner than a human hair!

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What are Precious Metals Anyway?

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• Gold jewelry comes in hundreds of alloy
types
 Yellow, white, red gold are most common
 Silver (Ag) and copper (Cu) are most common
alloying alloys
Types of Gold Jewelry
Source: https://en.wikipedia.org/wiki/Gold
• Jewelry is the most pawned item in the world
 Gold, silver, diamond, gems, pearls

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Gold Jewelry – Karat Terminology
Not to be confused with the
“carat” unit used to describe
the weight of diamonds:
1 carat = 200 mg

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Gold Testing Methods – The Biting Test …. Ouch!
Pro -- easy to use, affordable Con -- …. !!

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• Determines the approximate concentration of gold
• Scratch a jewelry item on a testing stone and apply a series of acids to the
scratch residue
 Acids test to the nearest karat (typically 10, 14, 18, and 22)
Gold Testing Methods – Acid / Scratch Test
Inexpensive and easy to obtain
Can be fooled by resistant materials
Semi-quantitative and subjective
Does not report the actual gold amount
Is it 14k gold or not?
Harmful -- can burn / blister skin
Destructive

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Semi-quantitative
• At gold price = $1,200/oz
• Value of a 25 gram chain
 10K = $402
 14K = $563
 18K = $724
 22K = $885
• Every 4k represents $161 in value
Can be fooled by stainless steels
• Necklace below has an engraving “0.750”
(equivalent to 18 karat)
• Passed as white gold
• Real composition? Not a spec of gold!
• What is it? stainless steel
(Fe=71.90, Cr=12.71, Mn=8.70, Ni=4.29, Cu=2.37)
The Problem with the Acid Test

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Semi-quantitative
• At gold price = $1,200/oz
• Value of a 25 gram chain
 10K = $402
 14K = $563
 18K = $724
 22K = $885
• Every 4k represents $161 in value
Can be fooled by stainless steels
• Necklace below has an engraving “0.750”
(equivalent to 18 karat)
• Passed as white gold
• Real composition? Not a spec of gold!
• What is it? stainless steel
(Fe=71.90, Cr=12.71, Mn=8.70, Ni=4.29, Cu=2.37)
The Problem with the Acid Test
*Assumptions: Gold @ $1,150/oz., necklace weighs 25 grams

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• Gold content determined by electrical conductivity
• Cost ≈ $150-$800; non destructive
• Limited gold-plating detection capability
• Restricted to 2-3 elements
• Requires calibration and cleaning of the sensor tip
• Operation outside of optimal range may decrease accuracy
Gold Testing Methods – Electronic Testers

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• XRF = X-Ray Fluorescence
• Surface technology for elemental analysis
• Sophisticated method in an incredibly easy-to-use interface
Light weight and rugged
Portable
Instant, actionable data for quick decision making
Near lab accuracy
Multi-element analysis
Non-destructive
Gold Testing Methods – Portable XRF

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How Does Portable XRF Work?
1. Primary x-ray ejects K-shell
electron
2. Electrons from higher shells fill in
the gaps
3. Differential energy state is
released as fluorescence x-rays
(element-specific)
4. The x-ray energies are analyzed and
compared with a built-in alloy library
5. Output:
- Spectra
- Positive grade identification
- Elemental composition
- Match level (0-4)

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• A common method to determine the purity of gold artifacts
• Consists of a complex, multi-step chemical process, which separates
gold from the rest
 Requires the storage, usage, and
disposal of harsh chemicals
 A destructive method
 Capable of detecting only a few
precious metals (typically gold)
 Very accurate, IF and ONLY IF,
done correctly!
XRF vs the Gold Standard Method -- Fire Assay

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Precious Metals XRF Analyzers: Options
Same analytical performance.
Both backed by comprehensive service & maintenance programs.
• Elegant retail design
• Windows keep jewelry in sight
• Built-in camera & Small Spot
• Ultimate in portability
• Tests any size object
• Comes with test stand
Handheld Desktop

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AuDIT
Thermo Scientific Au Detection &
Identification Technology
Patented
Only from Thermo Fisher Scientific
Immediately identify gold-plated jewelry
of light-to-medium thickness
Gold Plating Detection with Niton XRF Analyzers

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Niton AuDITOR Payback Calculator

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Certification and Leasing Programs

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• Jewelry is the most pawned item in the world
• Precious metals jewelry includes gold, silver, and platinum
• The need to determine accurately the gold content in jewelry and other
artifacts is greater than ever
• There are several commercial methods used to measure the content of
gold and other precious metals
• Portable XRF is a cost-effective, accurate, non-destructive, and user-
friendly method
Summary and Conclusion

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Thank You!
For more information, visit
www.thermoscientific.com/portableid
Or contact Jonathan Margalit @
jonathan.margalit@thermofisher.com
1-978-215-1649 or 1-800-875-1578