What looks like gold isn’t always gold — and even when it is, purity can vary. That’s why assaying remains essential. Whether you’re recycling jewelry, brokering bullion, or managing electronic scrap, knowing exactly what’s in your metal protects both value and trust.
To assay gold is to verify its content and purity using proven scientific methods. It’s the first step in any serious transaction involving precious metals — and it must be done right.
At Ledoux & Co., we’ve specialized in accurate, unbiased gold assays since 1880. As an ISO 17025 accredited lab, our results are trusted across industries — from local refiners to global manufacturers. In this guide, we’ll break down what gold assaying is, how it works, and why certified testing matters more than ever.
What Is a Gold Assay? The Science Behind the Term
A gold assay is the process of testing a sample to determine its gold content and purity. Unlike a basic “gold test” that might reveal only the presence of gold, an assay delivers a precise measurement of how much gold is actually there — often down to parts per million.
In professional settings, assays aren’t optional. They’re essential for validating the value of material before it’s bought, sold, refined, or reported. For precious metal recyclers, refiners, and traders, assays support pricing accuracy, risk management, and regulatory compliance.
Gold assaying is different from appraisal. While appraisals estimate market value based on weight and appearance, assays focus on exact composition using scientific methods — often required for tax documentation, industrial processing, or legal transactions.
Top 3 Gold Assay Methods Explained
Not all gold testing is created equal. Different situations call for different assay methods — each with its own strengths, limitations, and level of precision. Here are the most widely used techniques in the industry today:
Fire Assay
Fire assay is considered the gold standard for accuracy — and for good reason. This method melts a sample at high temperatures to separate and measure its precious metal content. It’s highly precise and ideal for high-value samples where even small deviations matter.
- Pros: Extremely accurate, reliable for both gold and other precious metals
- Cons: Destructive (the sample is consumed), slower turnaround
- Best For: Financial transactions, refining, high-purity verification
X-Ray Fluorescence (XRF)
XRF is a non-destructive testing method that bombards the sample with X-rays to analyze its surface composition. It delivers fast results and is commonly used for scrap sorting, quality checks, and field assessments.
- Pros: Fast, non-destructive, portable
- Cons: Surface-level analysis only; limited accuracy for impure or coated materials
- Best For: Quick scans, recycling facilities, jewelry verification
Inductively Coupled Plasma (ICP-OES/ICP-MS)
ICP analysis involves dissolving a sample in acid and analyzing it using plasma-based technology. It’s more precise than XRF and less destructive than fire assay — ideal when multi-metal detection is needed.
- Pros: High sensitivity, suitable for trace-level analysis
- Cons: Requires lab equipment and sample prep
- Best For: Complex materials, electronic scrap, multi-metal assays
At Ledoux & Co., our lab is equipped with all three — ensuring we use the most suitable method based on your sample type, purpose, and required precision. That’s how we maintain both accuracy and efficiency, no matter the material.
When testing circuit boards or electronics, this is especially useful — read about circuit board gold removal.
Why Lab Accreditation Matters: Trust, Standards, and ISO 17025
When it comes to assaying gold, accuracy isn’t a luxury — it’s a requirement. That’s why lab accreditation is critical. Anyone can run a test, but only an accredited lab can prove their methods, processes, and results meet globally recognized standards.
ISO 17025 is the international standard for laboratory competence. It ensures a lab can consistently produce valid results using approved methods and calibrated instruments. For gold assaying, this means confidence in the numbers — especially when real money or legal contracts are involved.
Whether you’re submitting gold for refining, settlement, or resale, ISO 17025 accreditation confirms that the lab’s results are:
- Scientifically sound
- Traceable to global measurement standards
- Accepted in international trade and finance
Who Needs Gold Assaying & When?
Gold assaying isn’t just for bullion dealers or big refiners — it plays a critical role across industries. Whenever gold changes hands, value is negotiated, or material is processed, a trusted assay becomes the anchor of the transaction.
Refineries & Smelters
Before gold can be melted, purified, or sold, its composition must be verified. An accurate assay helps refineries determine process needs and settle payments with suppliers confidently.
Recyclers & Electronic Scrap Handlers
Recyclers dealing with complex materials like circuit boards or industrial byproducts rely on assays to uncover valuable metals buried in the mix. Knowing the exact gold content ensures nothing is undervalued — or overlooked.
Jewelers & Manufacturers
For businesses working with raw gold alloys or scrap, assaying protects against material discrepancies. It ensures product quality, builds trust with clients, and supports internal quality control.
Investors & Brokers
When precious metals are traded or certified for storage, a formal assay adds legitimacy. Especially in private or over-the-counter trades, lab results serve as proof of value — and peace of mind.
International Trade & Customs
Accurate gold assays are often required for cross-border shipments to meet regulatory standards. Without them, delays, disputes, and fines can follow.
Across all of these industries, what matters most is independence, accuracy, and traceability. That’s why businesses — from multinational corporations to small family-run shops — turn to Ledoux & Co. for certified, commercial-grade gold assay results they can trust.
Why Work with Ledoux & Co. for Gold Assaying?
When precision and accountability matter, experience isn’t optional — it’s essential. At Ledoux & Co., we’ve spent over 144 years helping clients uncover the truth behind their metals with certified, data-driven assays. Here’s what sets us apart:
Scientific Integrity Meets Real-World Reliability
Every assay we perform is backed by our ISO 17025 accreditation, meaning our methods, documentation, and quality systems meet the strictest global standards. We don’t just test metals — we deliver results you can act on with confidence.
Trusted for Commercial Transactions
Ledoux’s gold assay reports are commercial grade and used for umpires, control purposes, and financial exchanges.This means clients across industries rely on our data for decisions that require precision, trust, and legal defensibility.
Ledoux & Co.: Get Trusted Gold Assay Results
Gold assaying is essential to ensuring fair value, compliance, and trust in every transaction involving precious metals. Whether you’re refining, recycling, or investing, accuracy matters — and so does who you trust to deliver it.
With over 144 years of experience and ISO 17025 accreditation, Ledoux & Co. provides precise, commercial-grade assay results backed by science, not guesswork.
Need certainty in your gold content? Submit a sample or reach out to our experts to see how we can help.
