How to Decode the Hallmarks on Your Jewelry

Author: Jewepiter Team

Do you know what the letters and numbers on your jewelry mean? They are called hallmarks, and they can tell you a lot about the quality, origin, and history of your precious metals. 

In this post, you will learn how to decode the hallmarks on your jewelry and discover the secrets behind the symbols and markings. This will help you to identify and value your jewelry, as well as to impress your customers with your knowledge and expertise.

Analysis of Letters and Numbers on Gold Jewelry

How to Decode the Hallmarks on Your Jewelry 1

Gold Purity Markings

Meaning of the “K” Marking

Explanation of Gold Percentage: In gold jewelry, “K” stands for Karat, indicating the purity of gold. The number following the K shows the percentage of gold in the alloy. For example, 24K represents pure gold, i.e., 100% gold.

Common Karat Marks and Their Meanings:

24K Gold: 100% pure gold, the highest purity, with a bright luster.

22K Gold: Contains 91.7% gold, with a deeper color and softer texture.

18K Gold: Contains 75% gold, hard and durable, suitable for setting gemstones.

14K Gold: Contains 58.3% gold, higher hardness, good wear resistance.

10K Gold: Contains 41.7% gold, the legal minimum Karat standard in the United States.

International Standards and Regional Differences

Differences in Markings by Country

International Differences in Gold Markings: Different countries have different methods of marking gold. In the United States, Karat numbers are commonly used, while in Europe, a thousandth percentage method is often used.

10K Gold Marking in Europe: Approximately 417, indicating 41.7% gold content.

14K Gold Marking in Europe: Approximately 585, indicating 58.5% gold content.

18K Gold Marking in Europe: Approximately 750, indicating 75% gold content.

Case Study: Comparison of Marking Methods in the USA and Europe

In the United States, gold jewelry is typically marked with Karat numbers, such as 14K, 18K.

European markets prefer the thousandth percentage method, such as 750 for 18K gold.

For gold jewelry processed in China targeting the American or European market, it is necessary to produce and mark according to the standards of the respective country to ensure the product meets the market requirements and regulations.

The Meaning of Letters and Numbers on Platinum Jewelry

How to Decode the Hallmarks on Your Jewelry 2

Platinum Purity Markings

Understanding the “Pt” Marking

Meaning of the Pt Marking: In platinum jewelry, “Pt” is the chemical symbol for Platinum. This mark is used to indicate the amount of platinum in the jewelry. Platinum is a precious metal, widely used in high-end jewelry manufacturing due to its rarity, purity, and durability.

Meaning of Numbers Following Pt: The number after the Pt mark indicates the percentage of platinum in the alloy. The higher the number, the higher the purity of the platinum.

Common Pt Content Marks and Their Meanings:

Pt1000: Represents pure platinum, i.e., 100% platinum, very rare and pure.

Pt950: The most common mark for platinum, containing 95% platinum mixed with 5% other metal alloys to increase hardness.

Pt900: Contains 90% platinum, with the remaining 10% being other metals, often used for casting complex and delicate jewelry.

Pt750: Contains 75% platinum, mixed with 25% other metals, a stronger alloy compared to Pt950 or Pt900.

The Meaning of Letters and Numbers on Silver Jewelry

How to Decode the Hallmarks on Your Jewelry 3

Silver Purity Markings

Understanding the “S” Marking

Representation of Silver Content: The “S” is commonly used to denote the purity of silver (Silver). The number following the “S” on silver jewelry indicates the percentage of silver in the alloy.

Common Silver Jewelry Markings and Their Meanings:

S999: Represents almost pure silver, with a silver content of 99.9%.

S925: The most common silver jewelry marking, known as “sterling silver” or “standard silver,” with a silver content of 92.5%. The remaining 7.5% is usually other metals, added to increase hardness.

S800: Silver content of 80%, more commonly seen in antique silverware and silver ornaments.

International Silverware Standards

Different Marking Methods by Country

Global Standards Differences for Silverware: Different countries have varying methods of marking silverware purity.

In Western countries, standard silver is often marked as S925, indicating 92.5% silver content.

Eastern countries, like China, also use the S925 marking but may also use S999 to indicate higher purity silver.

Some European countries have their unique marking systems, like the British hallmarking system, which not only indicates purity but also includes the year of manufacture and place of production.

The Meaning of Letters and Numbers on Stainless Steel Jewelry

How to Decode the Hallmarks on Your Jewelry 4

Stainless Steel Material Identification

Explanation of the “SS” Marking

Meaning of the SS Marking: On stainless steel jewelry, “SS” stands for “Stainless Steel.” This marking confirms that the main material used in the jewelry is stainless steel, a metal popular for its corrosion resistance and durability.

Different Stainless Steel Jewelry Imprint Markings and Their Meanings:

316L: The “316L” marking on jewelry signifies the use of medical-grade stainless steel, skin-friendly material suitable for sensitive skin.

304: The “304” marking on stainless steel jewelry represents a common type of stainless steel known for good corrosion resistance and cost-effectiveness.

Surgical Steel: Some jewelry may bear the “Surgical Steel” marking, indicating that the jewelry is made of high-grade stainless steel suitable for surgical applications, especially ideal for body piercings.

The Meaning of Letters and Numbers on Diamond Jewelry

How to Decode the Hallmarks on Your Jewelry 5

Diamond Grades and Markings

GIA Grade Marking

Meaning of the GIA Marking: The GIA (Gemological Institute of America) provides authoritative assessments of diamond quality, primarily based on four criteria: clarity, color, cut, and carat weight (the four Cs).

Examples of Letters and Numbers in GIA Grading:

Clarity Grades: For instance, IF (Internally Flawless), VVS1 and VVS2 (Very Very Slightly Included 1 and 2), VS1 and VS2 (Very Slightly Included 1 and 2), SI1 and SI2 (Slightly Included 1 and 2).

Color Grades: Ranging from D (completely colorless) to Z (noticeably colored). For example, D grade indicates completely colorless, very rare and expensive; G grade is near colorless, offering good value; K grade starts showing slight color.

Cut Grades: Evaluating the brilliance and fire of the diamond. For example, Excellent, Very Good, Good.

Carat Weight: 1 carat equals 200 milligrams. For instance, a 0.5-carat diamond weighs 100 milligrams.

Diamond Certification and Standards

Differences in Markings by Certification Bodies

Comparison of Markings by Major Diamond Certification Bodies: Different organizations may have varying grading standards, but GIA’s grading is widely considered the international benchmark.

AGS (American Gem Society): Focuses on cut quality, using a grading scale from 0 to 10.

HRD (Hoge Raad voor Diamant): Widely recognized in the European market for its stringent standards.

Tutorial: How to Read a Diamond Certificate

Thoroughly understand the grading information of the four Cs.

Pay attention to the description of the diamond’s proportions and symmetry.

Verify the security features on the certificate, such as watermarks and holograms, to ensure authenticity.

Additional Symbols Beyond Letters and Numbers

In the jewelry industry, apart from the common letter and number markings, there are also other symbols and marks that play a crucial role in the identification and valuation of jewelry.

Other Important Jewelry Markings

Manufacturer and Brand Logos: Many jewelers and manufacturers engrave unique logos or marks on their pieces, which help identify the brand or source of manufacture.

Country and Regional Symbols: Some countries require jewelry to be marked with specific codes denoting the country or region of manufacture.

Patent Numbers or Copyright Marks: These marks indicate that the jewelry design is legally protected against imitation.

Limited Edition and Serial Numbers: For limited production jewelry, manufacturers may add serial numbers to denote the item’s uniqueness within a specific series.

Date Marks: Some jewelry pieces are engraved with their production date, especially antique items, helping to determine their history and value.

Gemstone Source and Ethical Mining Marks: With increasing emphasis on sustainable and ethical mining, some jewelry pieces may be marked to indicate the source of the gemstones, certifying compliance with ethical mining standards.


It is crucial for jewelers, especially when custom manufacturing jewelry, to understand and utilize various markings. Correct markings not only ensure compliance with the regulations and standards of the selling country but also help jewelers accurately identify and purchase the required material products.

By mastering various markings and international regulations, jewelers can more effectively manage their supply chains, ensuring that products meet international standards and offer high-quality jewelry that meets customer expectations.

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