Jewelry Guide: Marks & Signatures

Hallmarking practices have ancient origins, with formalized systems appearing in France in the 13th century and Great Britain during the 14th century. These early identification symbols stamped on jewelry verified both material purity and maker identity through registered marks, and are relatively easy to decipher if the piece has been well preserved. The practice spread globally, with the United States implementing the National Gold and Silver Stamping Act of 1906, which mandated accurate purity markings. In 1961, further regulations required manufacturers to include makers’ marks alongside purity indicators.

Understanding jewelry marks and signatures is essential for collectors, connoisseurs and enthusiasts. These identifying marks provide critical information about a piece's authenticity, origin, materials and historical context. This guide examines the significance of these marks to help you authenticate and date your fine jewelry.

What Is a Jewelry Maker’s Mark?

A jewelry maker’s mark is one of the most important identification symbols stamped on jewelry. It helps collectors and experts identify who made a particular piece of jewelry, whether it is a modern creation or one of many valuable antique pieces. A jewelry maker’s mark may consist of initials, symbols, logos, or registered trademarks that distinguish one brand or jeweler from another.

While purity marks indicate a metal's composition, a jewelry maker’s mark often reveals the company or artisan responsible for the design and manufacture of the jewelry piece. These marks can be especially valuable when researching older jewelry, as they may help date the jewelry, establish its provenance, and confirm authenticity. In many cases, the mark also reflects a maker's reputation for quality and craftsmanship.

Historically, maker’s marks are usually found alongside purity stamps that indicate precious metal content. In some countries, additional hallmarks, such as a date letter, were also used to certify when and where a piece was made. Identifying these marks can trace a piece to renowned designers and houses such as Tiffany & Co., Cartier, Van Cleef & Arpels, and others. For collectors, maker’s mark identification is often one of the first steps in evaluating a valuable jewelry item.

Precious Metal Marks

Gold Purity Marks

Gold purity is indicated through two primary systems:

• Karat system: Two digits followed by "K" (e.g., 18K)
• Sometimes represented by “AU”, which comes from the Latin word Aurum, meaning gold
• Millesimal fineness: Three-digit number representing parts per thousand (e.g., 750)

Important Note: Jewelry marked with HGE (Heavy Gold Electroplate), GE (Gold Electroplate) or GF (Gold Filled) contains minimal gold content applied over base metals such as copper.

Silver Purity Marks

The term "sterling" appeared in England around the 12th century, and the initial standard was eventually set at 925 parts silver per 1000 (92.5%). Hallmarking was established in London by 1300, requiring the "sterling" standard and enforcement was strict, with substandard pieces destroyed.

Throughout the 19th century, mass production and electroplating disrupted the silver industry, and there was not yet a global standard. Germany, for example, had 800 or 835 parts per thousand, France 800 or 950 and Russia 875. By the early 20th century, though, particularly through the United States’ legislation, 92.5% became a common standard for silver.

Sterling silver (92.5% pure silver) is denoted by:

• "925"
• "STERLING"
• "STG"
• "STER"

Important Notes:

"German silver" or "nickel silver" contains no actual silver and is composed of copper, nickel and zinc.

Platinum Purity Marks

Platinum did not gain prominence in jewelry and luxury items until the late 19th century. Unlike silver, platinum's extreme melting point (1,768°C) made it difficult to work with until modern techniques were developed. When platinum emerged as a luxury metal, various standards were established globally.

Platinum purity is typically marked as:

• "PLAT" or "PT" followed by the fineness number
• "950" (95% pure platinum, common in European pieces)
• "900" (90% pure platinum, historically used in American pieces)
• "850" (85% pure platinum, less common)
• "PT950" or "PLAT950" (modern international standard)

The United States established legal standards for platinum in 1976, requiring items to contain at least 950 parts per thousand pure platinum to be marketed as platinum. Items between 850 and 950 parts per thousand must be marked with their exact fineness.

Important Note: Unlike gold and silver, platinum is rarely alloyed with base metals.

Dating Terminology

Understanding chronological terms is crucial when discussing jewelry:

• Antique: Items over 100 years old
• Vintage: Items over 20 years old
• Retro: Typically refers to mid-century designs (1930s-1950s)

Jewelry Maker's Marks Common Locations

While marks are often placed in hidden yet accessible locations, their exact placement varies depending on the type of jewelry. These stamps are commonly found in discreet areas that do not interfere with the beauty of the piece.

Necklaces and Pendants

On a necklace or pendant, the maker's mark is frequently found near the clasp or on the clasp of a necklace itself. Some makers place the stamp on a small tag attached to the chain, while others engrave it directly onto a connecting ring. If examining a pendant, check the mark on the back, particularly along the bail or attachment point.

Rings

For rings, the hallmark and maker's mark are typically stamped inside the ring band. This protected location helps preserve the marking over time while remaining unobtrusive. When inspecting a ring, use a magnifying glass or jeweler’s loupe to clearly view worn or partially obscured markings.

Bracelets

A bracelet may feature its maker's mark on the inside surface, on a connecting link or near the fastening mechanism. Many luxury manufacturers stamp their marks close to the closure, making them easier to locate without disrupting the design.

Earrings

An earring often contains markings on the post, clip or backing component. Due to their smaller size, earring marks can be difficult to read and may require magnification. Some makers also place marks on the reverse side of decorative elements to maintain a clean appearance.

Authenticating Jewelry Through Marks

When examining jewelry marks:

1. Use magnification to clearly view marks
2. Document observed marks
3. Research marks in reference guides or databases
4. Consider consulting experts for rare or ambiguous marks
5. Verify consistency of marks with the piece's apparent age and style

Maker’s Marks You Should Know:

Tiffany & Co.