Expert Tips for Identifying Valuable Antique Jewelry

Many individuals may unknowingly possess valuable antique jewelry, with some pieces mistaken for costume jewelry potentially holding significant worth. This was highlighted when a grandmother's collection, stored for decades, fetched over £500,000 at auction in London, far exceeding its initial estimate.

Jewelry valuer Karra Ellison, with over 13 years of experience, notes that rising metal prices, a push for sustainability, and a renewed appreciation for vintage items have increased the value of old jewelry. "Jewelry which has often sat at the bottom of jewellery boxes could now hold more value than you'd think," Ellison stated. She recounted instances where clients planned to discard or repurpose items that turned out to be valuable, including a ruby and diamond bangle estimated at £60,000.

Ellison offers guidance on identifying potential treasures, cautioning that while some indicators are useful, professional appraisal is often necessary.

Hallmarks

Hallmarks, typically small inscriptions on jewelry, can indicate the purity of the metal. For example, '375' signifies 9-carat gold, '585' indicates 14-carat gold, and '750' represents 18-carat gold in the UK, applied by an Assay Office. However, Ellison warns that these marks can be forged to deceive buyers, especially with rising precious metal costs. "Be prepared for what may appear to be a hallmark or stamp of purity may be forgery," she said.

Diamonds and Gemstones

Identifying diamonds and other gemstones accurately is best left to professionals. Ellison dismisses the reliability of viral diamond-checking apps and image-based identification tools, stating, "There are some remarkably interesting apps available that claim they can identify gemstones and diamonds from an image however; I can say with full confidence that this is not possible." These methods cannot determine the stone's identity, whether it's natural or synthetic, or if it has undergone treatments.

For accurate authentication and valuation, Ellison recommends contacting a registered local valuer. Professionals registered with gemological organizations possess the necessary diplomas and ongoing training to identify stones, treatments, and current market values.

Ellison also cautions against relying solely on thermal conductivity testers, as both synthetic moissanite and some synthetic diamonds can yield a positive reading for diamond. Distinguishing between them often requires an electrical conductance probe, though even this can be complicated by boron doping in some synthetic and natural blue diamonds, which can affect their conductivity.

Assessing Authenticity

The Cut of a Stone

The cut of a gemstone or diamond, even if it appears 'old-fashioned,' does not guarantee its authenticity. Ellison has observed synthetic diamonds cut in traditional styles to mislead buyers, particularly at auctions. "Don't just assume that because it looks old it is genuine," she advised, noting that materials like paste (lead glass) and synthetic rubies and sapphires have existed for centuries.