Dating Jewelry - Precious Metal Hallmarks

The use of hallmarks on jewelry and objects made from precious metal began in the 1400’s, however many unmarked pieces exist. The passage of time and repair work has marred or eliminated marks from many pieces making them harder to identify the precious metal content, the country of manufacturer or the maker.

EUROPEAN MARKINGS

The British hallmark used from 1798 to 1854, is a crown, while in Scotland, the hallmark is a thistle. The British only used 18 or 22 karat gold during this time. The karatage is usually the karat number, followed by a c, ct, or carat. It may be marked 750 or 916, as well. After 1854, the British begin to hallmark jewelry pieces made in 9, 12, and 15 karat gold as well and the crown is still used, however, the karatage is indicated with a mark that denotes the fineness in parts per thousand, for example the mark 375 is nine karat, 500 is 12 karat, and 625 is 15 karat. In 1932, 14 karat, often marked 585, replaced 12 karat and 15 karat alloys. In addition to the crown and fineness marks, assay marks and date letters are used that provide a great deal of information about a piece. British silver pieces will normally have the lion passant hallmark (indicating sterling silver) along with an assay mark, a date mark, and sometimes a maker’s mark.

French gold pieces made after 1838 bore an Eagle hallmark indicating a fineness of at least 18 karat and assayed French pieces must meet or exceed this standard. French Silver pieces will have either, a Boar’s Head or Crab hallmark. In 1910, the Dog’s Head mark replaces the eagle mark on earlier French platinum pieces and French pieces may have a maker’s mark.

Hallmarking systems are developed and implemented in Austro-Hungary, Russia, Sweden, and Finland in the 19th century. Silver fineness varies widely, and silver alloys that range from 75% to 95% purity are used. Marks such as 750 or 950 generally indicate the purity of the silver.

U. S. STANDARDS

Some marks are confusing because they closely resemble legitimate hallmarks. American sterling and silver plated objects have hallmarks that resemble the English hallmarking system. The American jewelry makers used hallmarks, which could easily be confused with karatage marks.

Before 1978, the Federal Government allows U.S. jewelry makers a tolerance of up to ½ karat when making goods for sale. That means an old piece marked 14k could easily have a fineness of only 56%, instead of the 58.5% associated with 14 karat gold. The Plumb Gold standard introduced in 1978 reduced quality variance from approximately 20 parts per thousand, to 3-7 parts per thousand. Many makers put a “P” after their karat mark to indicate compliance with this higher standard.

In addition to the longstanding hallmarking standards of some European countries, the United States enacted the Gold and Silver Stamping Act in 1906. This required that a manufacturer put a quality stamp on his karat gold or silver items along with their hallmark. These marks aid in identifying and dating a piece. During the process of sizing a ring, replacing a chain or from normal wear, marks can disappear.

ROLLED GOLD PLATE AND GOLD FILLED

During the late 18th to early 19th century rolled gold plate is developed. Similar to the Sheffield plate process, it involves the lamination of a sheet of gold to a sheet of base metal. Gold filled is a variation of this process and both are normally marked. Rolled Gold plate marked RGP can vary in the karatage and in the thickness of gold used. Gold filled is normally marked with the karatage and a separate mark indicating the quantity of precious metal used. A mark such as “1/10 12k.g.f.” indicates the piece has a bonded 12-karat surface and the amount of gold used is equal to at least 1/10 of the piece’s entire weight. The karatage and the quantity can vary, with some pieces only having 1/2 of the total weight in the gold finish. Most U.S. manufacturers switched from the 12 karat gold finish to a 14 karat gold finish in the 1970’s and 80’s, indicated by 14k.g.f.

Gold filled finishes, which can be done in any karatage, can also be produced in various colors of karat gold-yellow, white, green, and pink (or rose).

It should be noted that one well known American maker, Krementz & Co., did not mark most of their gold filled pieces with any indication of quality. On most pieces, you will only find the name Krementz, or sometimes their stylized hallmark. They felt their product was so superior to other manufacturer’s processes that it was not necessary for them to mark the pieces as gold filled, referring to their product as Krementz Overlay.

During WWII, a time when base metals were scarce for jewelry production, Gold-filled finishes over sterling are used, with some finishes having a tendency to darken and tarnish through to the gold surface over time. Manufacturers continued to produce jewelry of this type after the war, up until the 1950’s. You may encounter some jewelry items with markings such as SemiMetallic and BiMetallic, which are copyrighted names for one particular manufacturer’s version of the process.

One of Ruby Lanes listing requirements for the ‘jewelry lane’ states: The manufacturer’s mark (where present) must be illustrated and clearly readable. Meaning, all marks applied by the maker of the piece, including hallmarks, quality marks, and assay marks are to be illustrated. This is a good rule to follow for anyone selling jewelry with gold content on the Internet.

 


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