Highlights

• A Certificate of Analysis (COA) is a formal laboratory document that verifies rare earth material quality, composition, and purity.
• COAs serve as the foundation for trust, pricing, and regulatory compliance in critical mineral transactions.
• COAs typically include:
  • Rare earth content breakdown (TREO)
  • Impurity profiles including radioactive elements
  • Physical specifications
  • Batch traceability tied to specific analytical methods and standards
• Issued by producer labs or independent third-party testing firms, COAs enable:
  • Payment terms
  • Dispute resolution
  • Regulatory compliance
• Practices vary between Chinese GB/T standards and international ISO/ASTM frameworks.

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A Certificate of Analysis (COA) is a formal laboratory document that reports the results of analytical testing performed on a material. Issued and signed by an authorized laboratory representative, the COA provides assurance that the product conforms to stated specifications and accurately represents what is being sold. In practice, it functions as a verification-of-quality document, structured according to industry standards or regulatory expectations to ensure consistency, traceability, and credibility.

Why COAs Matter for Rare Earth Elements

In the rare earth element (REE) industry, COAs are foundational to trust and price discovery. Rare earth materials—whether concentrates, oxides, metals, or alloys—vary widely in composition and purity, and those differences directly affect value, processing behavior, and end-use performance. Even small analytical inaccuracies can result in mispriced transactions, processing failures, or contract disputes. For example, overstating the purity of neodymium-praseodymium oxide can lead magnet manufacturers to overpay or experience downstream performance issues.

As rare earths underpin critical technologies—from electric vehicle motors and wind turbines to defense and aerospace systems—buyers, regulators, and financiers increasingly demand verified analytical data before materials enter supply chains. The COA is the document that enables that verification.

What a Rare Earth COA Typically Includes

A COA for rare earth materials generally contains:

Rare Earth Content:

A breakdown of each rare earth element or oxide present, reported in weight percent. For oxides, the Total Rare Earth Oxide (TREO) content is commonly stated as a summary indicator of material value. For metals and alloys, a comparable total rare earth metal content may be used.

Impurity Profile:

Non-rare-earth impurities—such as iron, silicon, calcium, or aluminum oxides—are listed, along with trace levels of other rare earths not part of the primary product. High-purity materials often report impurities at parts-per-million levels, while concentrates may show percentage-level impurities. Importantly, radioactive elements such as thorium (Th) and uranium (U) are typically disclosed due to regulatory, handling, and transport implications.

Physical and Technical Specifications:

Depending on contract requirements, COAs may include moisture content, particle size distribution, phase composition, or other physical parameters relevant to processing or performance. Analytical methods (e.g., ICP-OES, ICP-MS) and applicable standards are often referenced.

Batch Identification and Traceability:

Each COA is tied to a specific lot or batch and includes sample identification, analysis date, issuing laboratory, and formal approval by a responsible chemist or quality officer. This traceability is essential for audits, dispute resolution, and regulatory compliance.

When COAs Come Into Play in Transactions

COAs typically enter the transaction process after production but before final acceptance. Sellers provide a COA as part of shipment documentation, confirming that the material meets contractual specifications. Payment terms often reference COA results, with penalties or rejection rights triggered if purity or impurity thresholds are not met.

Many buyers independently test retained samples or commission third-party assays to verify seller-provided COAs. In the event of discrepancies, contracts commonly designate an independent “umpire” laboratory whose analysis is binding. This practice is formalized in several jurisdictions, including China, where supplier-issued quality certificates can be challenged through third-party arbitration testing.

Beyond private transactions, COAs are increasingly required for regulatory and policy compliance. In the United States, for example, producers seeking critical-mineral tax incentives must substantiate purity thresholds, typically supported by laboratory analysis. In Europe, COAs often underpin import safety, environmental, and radioactivity compliance.

Who Issues COAs

COAs are issued either by producer in-house laboratories or by independent third-party testing firms. In China, large rare earth producers frequently rely on internal labs operating under national standards. In international and ex-China trade, buyers often prefer or require third-party verification to ensure independence.

Globally, dozens of accredited laboratories provide rare earth and critical mineral analysis. These include large multinational testing firms such as SGS, Intertek, Bureau Veritas, and ALS, as well as specialized assay laboratories like Ledoux & Company and Conti Testing Laboratories. National geological agencies and certified reference material providers also issue COAs for calibration and benchmarking purposes.

China vs. Ex-China Practices

While COA content is broadly consistent worldwide, differences exist in standards, language, and issuance practices. Chinese COAs typically reference domestic GB/T standards and may be issued directly by producers. Outside China, ISO and ASTM standards are more common, and independent verification plays a larger role. As China’s export control regime evolves, material analysis increasingly intersects with licensing and compliance requirements, reinforcing the COA’s regulatory importance.

Conclusion

For the Rare Earth Exchanges™ community, the Certificate of Analysis is not a formality—it is the backbone of rare earth commerce. It defines value, enables trust, governs pricing, and mitigates risk across borders and supply-chain tiers. As ex-China rare-earth and critical-mineral markets develop, reliable COAs will remain indispensable for transparency, credibility, and market formation.

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