What Do Jewelry Markings Mean & How To Confirm Metals

Hallmarking is a tradition that dates back to France in the 1200s. This process involves labeling metals to identify their composition in order to help inform and protect buyers.

Assay offices are places where metals can be tested and given an official marking to denote their purity. These offices exist throughout the world, each with their own governance and processes for testing metals, but many marking traditions are standardized for the sake of consumers.

Jewelry markings may include a mixture of information, but a primary emphasis is the type and composition of the metals included. Additional details include the location where any assessment and manufacturing occurred.

The most common markings found indicate details such as gold purity and include:

• 24K / 999 / 999.9: Most often used in investment-grade bullion and coins
• 18K / 750: High-end jewelry that benefits from increased durability
• 14K / 583 or 585: High-quality jewelry at a more accessible price point
• 10K / 417: Higher durability, but lower luster than high karat counts
• 925 or .925: Sterling silver marking indicating 92.5% of pure silver
• PT or PLAT: Platinum composition in house shaped box

Plated Metal Markings:

Some items, such as costume jewelry, may feature gold or silver elements, such as gold- or silver-plating over other less valuable materials such as brass, aluminum, or copper. To contrast, fine jewelry usually contains a high percentage of gold or silver, which adds to its value. In many cases there are visual markings that indicate if an item is plated:

• GP: An abbreviation for gold plated
• GEP: Gold electroplated, which is a form of plating that can have increased prevision
• EP: Electroplating technique was used with either gold or silver. If gold was used GEP is commonly used, but EP is used as an alternative that could indicate gold or silver.
• RGP: Rolled gold plating, which bonds a thin layer of gold to the material below it using high pressure
• VGP: Vermeil gold plate, which is a layer of gold on top of a base of sterling silver
• SP: Silver plated, a layer of silver electroplated onto another base metal
• EPNS: Electroplated nickel silver, commonly used for holloware and decorative objects
• GF: Gold filled, bonding a layer of gold to a base metal using heat and pressure

Jewelry and other items with plated metals markings have no precious metals value. In most cases plated items contain less than 0.05% of gold or silver.

Manufacturing & Designer Marks:

Some manufacturers and designers throughout the world also apply their own additional hallmarks. This is especially common for high-end pieces from companies such as:

• Tiffany & Co. (T & Co.)
• Cartier
• David Yurman (D.Y. or D. Yurman)
• Van Cleef & Arpels (V.C.A.)

What is a Spectrometer?

Spectrometers are an advanced and non-invasive way to analyze metals, including but certainly not limited to jewelry pieces. They work by analyzing the wavelengths that are either emitted or absorbed by the metal. This allows the tool to measure the exact composition of metals in a way that doesn’t cause any type of damage to whatever is being tested.

For example, spectrometers can definitively determine:

• If unmarked gold is 14K, 18K, 24K, another composition, or even counterfeit.
• What type of gemstones are used in a jewelry piece.
• The purity of any other metal types.

This type of verification is critical for ensuring any financial evaluations are completed with accuracy and appropriate offers are made to sellers.

Jack Hunt’s team uses a tabletop x-ray spectrometer (EDXRF), which provides accurate results in a matter of seconds without causing any type of damage to the items being tested. This equipment allows for further analysis with visual zoom levels up to 184x the original size of the item being sampled.

Marking Examples and Meanings:

Using the information from this resource, below are examples of markings and what they mean:

• Marked “925 Italy”: Sterling silver (92.5% pure) made in Italy.
• Marked “950 PT”: Made of 95% pure platinum and 5% other metals.
• Marked “14K 585”: 14 karat gold, which is 58.5% pure gold and 41.5% other metals.
• “Tiffany & Co. 750”: Designed and manufactured by Tiffany & Co. and is 18 karat gold (75% pure gold and 25% other metals).