How to date a piece of jewellery: hallmarks, clasps and cuts

A piece of jewellery is dated by reading several clues together: fineness and assay marks, the construction of the clasp, how the stones are held and how they are cut. Closed settings and rose-cut stones belong to the 18th century, C-shaped clasps without a safety catch to the period before about 1900, and platinum with milled settings and step-cut stones to Art Deco. Hallmarks often give the surest answer, since Swedish gold and silver jewellery carries letters for the year.

Facts

Begin with the hallmarks

Swedish jewellery in gold and silver must be hallmarked, and the marks are read as on silver: the name of the master or firm, the sign of the town, a date letter and three crowns showing that the fineness has been checked. With a hallmark chart the date letter can be translated into a specific year. How this is done is explained in the guide to silver hallmarks and in the diagram below.

The fineness is often given in numbers: 925 for sterling silver, 750 for 18 carat gold and 585 for 14 carat. In Britain, lower gold standards such as 9, 12 and 15 carat were permitted from 1854. Costume jewellery, that is, imitation jewellery of glass, plastic and base metals, has no fineness or assay marks, and neither does much older rural silver. The absence of hallmarks therefore does not mean that a piece is fake, only that it must be dated in other ways.

The setting and the cut

In the 18th century the stones were set in closed settings, where the back is covered with metal. Behind the stone there was often a foil that enhanced the colour and brilliance in candlelight. Diamonds were often set in silver with gold at the back, and the silver has darkened over time. Open settings, where light reaches the stone from behind, became common in the 19th century.

The rose cut has a flat back and a dome with a few large facets, and it belongs to the older jewellery. In the 19th century diamonds were cut with a high crown and a small table, in what is called the old cut, and the modern brilliant with calculated proportions dates from 1919. The more regular and sharp the facets, the later the cut – unless the stone has been recut.

The clasp and the back

Brooches of the 19th century often have a simple, C-shaped clasp in which the pin merely rests in the hook. The safety catch, in which a small rotating piece closes the hook, arrived around 1900. The pin on an older brooch is often long and sticks out beyond the edge. Earrings had hooks or loops for pierced ears for a long time; screw fittings and later clips made it possible to wear earrings without piercings.

The back reveals a great deal. Handwork shows as small irregularities, file marks and solder joints, whereas cast or stamped factory-made jewellery is smooth and often hollow. Chains with handmade links vary in size, whereas machine-made ones are exactly alike.

Materials that belong to a period

Around 1800 came cameos in stone and shell, often in complete parures, and during the wars against Napoleon jewellery of cast iron was worn. Mourning jewellery with hair and black jet became common in the 19th century; jet is light and feels warm, whereas black glass is heavier and cold. Hair jewellery from Våmhus in Dalarna belongs to the same century.

Art Nouveau jewellery, such as Lalique’s dragonfly, used enamel, horn and glass, and transparent enamel without a backing is called plique-à-jour. In the interwar years platinum with small diamonds in milled settings, millegrain, and baguette and step-cut stones became typical of Art Deco, as did Bakelite and glass in costume jewellery. After the war the Nordic silversmiths made smooth, sculptural jewellery, such as Vivianna by Vivianna Torun Bülow-Hübe from 1962.

Altered, repaired and newly made

Jewellery has always been altered. A brooch may have become a pendant, an earring may have been given a new fitting and stones may have been replaced or recut. A newer clasp on an old piece is therefore common and no sign of forgery, but it does not date the piece. Look for solder joints in a different colour from the rest of the metal.

Jewellery in older styles is also made today, and laboratory-grown stones can be told from natural ones only with instruments. An old piece should therefore be consistent in all its parts: the style, the metal, the hallmarks, the setting and the wear. See more jewellery, from Viking tortoise brooches to the silver of the 1960s, in the jewellery category.

How to recognise it

Exercise

A platinum diamond brooch has small bead-like edges around the stones and baguette-cut stones in a geometric pattern. When was it probably made?