Gold’s value isn’t just in its shine—it’s in its purity. Whether used in jewelry, electronics, or refining, the different grades of gold directly impact performance, pricing, and compliance.
Grades like 24K or 18K aren’t just labels—they define how much gold is actually present and how it will behave in use. Mistaking one grade for another can lead to costly errors.
In this guide, we’ll break down how gold is graded, what the numbers mean, and why understanding purity is essential for anyone working with precious metals.
What Are Gold Grades?
Gold grades are a way to express how much pure gold is present in a given item. These grades are most commonly measured in karats (K) or through the gold purity scale, known as millesimal fineness.
- Karats represent purity on a scale of 24. Pure gold is 24K, meaning all 24 parts are gold. An 18K item contains 18 parts gold and 6 parts other metals.
- Fineness uses a 1,000-point scale. Pure gold is marked as 999 or .999, while 750 fineness equals 75% gold (18K).
Both systems indicate gold content but are used in different industries and regions. Jewelers often reference karats, while manufacturers and refiners rely more on millesimal values for precision.
Karat vs Fineness: How Purity Is Measured
While both karat and fineness systems measure gold purity, they come from different traditions—and understanding the difference matters.
1. Karat (K)
Karat is the more familiar system in jewelry and consumer goods. It breaks gold into 24 parts:
- 24K = 99.9% pure gold
- 18K = 75% gold
- 14K = 58.5% gold
- 10K = 41.6% gold
The remaining parts are typically alloyed with silver, copper, nickel, or zinc to increase durability.
2. Fineness
Used more in industrial settings and refining, fineness expresses purity as a decimal over 1,000:
- 999 = 99.9% pure
- 750 = 75% pure
- 585 = 58.5% pure
This system is more precise, especially for technical applications like electronics or aerospace, where even small variations can affect performance.
Choosing between the two depends on your industry. Manufacturers and refiners benefit from the exactness of fineness, while jewelers may lean on karats for simplicity.
Knowing both ensures better sourcing, clearer documentation, and fewer surprises—especially when testing or selling gold across global markets.
Gold Grades in Practice: Jewelry vs Industry
Gold’s grade isn’t just about purity, it’s about purpose. The same metal that makes a wedding band gleam might also be powering a circuit board. The difference lies in how gold is used and what its grade demands.
1. In Jewelry
Higher-karat golds, like 22K or 18K, are popular for fine jewelry because of their rich color and value. But pure 24K gold, while visually appealing, is too soft for everyday wear. That’s why jewelers often alloy gold with harder metals to improve durability without sacrificing too much purity.
2. In Industry
In contrast, industrial gold uses demand precision and consistency. Electronics manufacturers rely on gold’s conductivity and corrosion resistance, but they don’t need visual appeal—they need engineered alloys that perform under pressure. Here, lower-karat or specially formulated gold alloys are common, often chosen based on exact metallurgical specs.
Understanding how different grades of gold function across applications is essential for sourcing, design, and recovery. Whether it’s about aesthetics or conductivity, strength or purity—grade defines gold’s role.
5 Common Grades and Their Characteristics
Not all gold is created equal and knowing the common grades helps determine what’s best for your needs, whether you’re producing, recycling, or buying.
24K Gold (99.9% Pure)
This is the purest form of gold available. It has a bright yellow hue and is highly malleable, which makes it unsuitable for most jewelry but ideal for bullion and some high-precision applications. It’s also widely used in electronics and dentistry where high purity is essential.
22K Gold (91.6% Pure)
A strong balance between purity and strength. Common in high-end jewelry across Asia and the Middle East, 22K gold is still relatively soft and not suitable for rugged wear.
18K Gold (75% Pure)
The sweet spot for jewelry — rich in gold content but alloyed enough to offer durability. When comparing 24K vs 18K gold, 18K is the practical choice for wearability without giving up too much purity.
14K & 10K Gold (58.3% and 41.7%)
Popular in commercial jewelry, these grades are more affordable and far more durable. While they contain less gold, their strength and scratch resistance make them ideal for everyday use.
Industrial Gold Grades
In industrial settings, gold isn’t categorized by karat like in jewelry. Instead, it’s alloyed with other metals to meet precise technical specifications — such as conductivity, hardness, or corrosion resistance. These engineered gold alloys are often defined by ASTM or ISO material standards, not a traditional grading system.
For example, gold bonding wires in microelectronics are typically 99.99% pure but alloyed with trace elements like beryllium or copper to enhance durability.
Each grade offers a different balance of purity, strength, and suitability—and choosing the right one depends entirely on your application.
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Why Purity Testing Matters
When it comes to gold, assumptions are costly. A small error in purity can lead to significant financial discrepancies, failed quality checks, or even regulatory setbacks. That’s why precision testing is non-negotiable.
Whether you’re buying, selling, refining, or manufacturing, knowing the exact grade of your gold ensures trust, compliance, and profitability. Visual assessments or basic tests aren’t enough, especially when high-value materials or legal documentation are involved.
This is where a certified precious metal testing lab becomes essential. By using industry-standard methods such as fire assay, instrumental analysis, or wet chemistry, laboratories can verify purity with commercial-grade accuracy.
Labs like Ledoux & Co. follow rigorous ISO 17025 protocols to deliver reliable assay results, often used in contracts, trade settlements, and compliance reports. These results are not only about numbers—they’re the basis for decisions, investments, and long-term relationships.
Choosing the Right Testing Partner
Gold purity analysis is only as reliable as the lab behind it. When the stakes involve financial transactions, legal compliance, or high-value materials, your testing partner must offer more than just basic results—they need to deliver confidence.
Here’s what to look for in a trusted lab:
- ISO 17025 accreditation for proven precision and traceability
- Transparent reporting, fast turnaround, and responsive support
- A reputation for independence, objectivity, and industry integrity
That’s why manufacturers, refiners, and recyclers across the globe rely on Ledoux & Co.. With over 140 years of metallurgical expertise, we offer commercial-grade assay results that meet the highest technical and regulatory demands. From precious metal analysis to on-site representation, our services are built to help clients reduce risk and operate with certainty.
Ledoux & Co.: Precision Gold Testing Laboratory Services
Understanding the different grades of gold is more than academic, it’s essential to making informed decisions in production, procurement, and precious metal recovery. From karat systems to millesimal fineness, each grading method serves a purpose, and each level of purity affects how gold performs, trades, or transforms.
But knowing the grade is only the first step. Verifying it with precision protects your investment, ensures compliance, and strengthens trust across the supply chain.
With ISO 17025-accredited services and a legacy of metallurgical expertise, Ledoux & Co. offers the assurance manufacturers and refiners need to move forward with confidence.
Need to confirm the purity of your gold?
Submit your sample to Ledoux & Co. and get commercial-grade results you can trust.
