Bonhams is a British international auction house founded in London in 1793, making it one of the oldest continuously operating auction businesses in the world. Headquartered in Knightsbridge, London, the house maintains salerooms across Europe, North America, and Asia, and conducts regular dedicated jewellery sales — marketed under the banner Important Jewellery — in London, New York, Hong Kong, and Edinburgh. Within the fine-jewellery and gemstone trade, Bonhams occupies a distinctive position: it attracts both private collectors seeking accessible entry-level lots and experienced trade buyers pursuing high-value signed pieces and exceptional loose stones.

History and Formation

The house traces its origins to 1793, when Thomas Dodd established an auction business in London dealing principally in books, prints, and works of art. Over the following two centuries the firm changed hands and names several times before the modern entity took shape through a series of consolidations. The most significant of these occurred in 2001, when Bonhams merged with Brooks, and again in 2002, when it acquired Phillips Son & Neale's British and European operations, substantially enlarging its footprint and its specialist departments. The resulting business adopted the trading name Bonhams 1793 to emphasise its historical continuity.

In 2022, Bonhams acquired Skinner, Inc., a well-regarded American regional auctioneer based in Boston and Marlborough, Massachusetts, with particular strengths in American furniture, Asian art, and jewellery. The acquisition meaningfully expanded Bonhams' North American reach beyond its existing New York and San Francisco salerooms, bringing an established client base and specialist expertise into the group.

Jewellery and Gemstone Sales

Bonhams holds multiple dedicated jewellery auctions each year across its principal salerooms. The London sales, typically staged at New Bond Street or the Knightsbridge premises, represent the house's flagship jewellery offering and have included signed pieces by major maisons — Cartier, Van Cleef & Arpels, Bulgari, and others — alongside estate jewels spanning Georgian through to mid-twentieth-century periods. Edinburgh sales draw heavily on Scottish private collections and frequently feature antique Scottish pebble jewellery, agate work, and Cairngorm-set pieces of regional historical interest.

Hong Kong sales position Bonhams within the competitive Asian jewellery auction market, where demand for fine jadeite, natural pearls, and top-quality coloured stones — particularly Burmese rubies and Kashmir sapphires — has driven strong results. The house's New York sales, reinforced by the Skinner integration, cater to American private collectors and estate consignors.

Across these venues, the catalogue range is notably broad. A single Bonhams jewellery sale may include a modest Victorian seed-pearl brooch alongside a certificated Burmese ruby ring accompanied by a Gübelin or GIA report. This breadth is a deliberate commercial strategy, widening the buyer pool beyond the ultra-high-net-worth segment that dominates the equivalent sales at Christie's and Sotheby's.

Gemstone Documentation and Laboratory Reports

For significant loose stones and high-value mounted pieces, Bonhams follows standard major-auction-house practice in requiring or strongly encouraging third-party gemmological certification. Reports from the Gemmological Institute of America (GIA), Gübelin Gem Lab, SSEF Swiss Gemmological Institute, and Lotus Gemology are routinely referenced in catalogue entries. Origin determinations — particularly for rubies described as Burmese, sapphires described as Kashmir or Padparadscha, and emeralds described as Colombian — are treated as material to value and are cited with the issuing laboratory identified. Treatments, where disclosed by the laboratory report, are noted in catalogue descriptions in accordance with the house's conditions of business.

Bonhams' specialist jewellery departments include qualified gemmologists who assess consignments prior to sale, though the house, like all major auction houses, relies on independent laboratory reports for definitive origin and treatment conclusions on important stones.

Market Position and Collector Appeal

Within the hierarchy of the international jewellery auction market, Bonhams sits below Christie's and Sotheby's in terms of aggregate annual jewellery turnover and in the frequency with which it achieves nine-figure or eight-figure individual lot results. However, this comparison is somewhat misleading as a measure of the house's significance. Bonhams consistently achieves strong results in categories where it has developed particular specialist depth — Scottish antique jewellery, Arts and Crafts and Aesthetic Movement pieces, and certain categories of Asian jewellery — and its broader lot-value range makes it a more accessible entry point for collectors building a collection rather than acquiring trophy pieces.

The house also benefits from its geographic diversity. Regional salerooms and the Skinner network in New England give Bonhams access to estate consignments that might not naturally flow to a London- or New York-centric competitor, and this pipeline of privately held material sustains a catalogue character that differs from the more internationally curated offerings of its principal rivals.

Buying and Selling at Bonhams

Prospective buyers may register to bid in person, by absentee order, by telephone, or online through the house's own platform. Buyer's premium rates are applied on a sliding scale consistent with major-market practice, calculated on the hammer price. Sellers consigning jewellery or gemstones are advised to contact the relevant specialist department directly; the house offers complimentary valuation appointments at its principal salerooms and, periodically, at regional venues.

Condition reports and additional photographs are available on request prior to sale, and the house's online catalogue infrastructure has expanded substantially in the post-2020 period to support remote bidding. Prospective buyers are reminded, as with all auction purchases, that catalogue descriptions — including any gemmological characterisations — should be verified against the original laboratory certificates where these exist, and that independent examination before bidding is advisable for significant purchases.

Further Reading

• Bonhams Jewellery Department — bonhams.com
• GIA Auction House Services — gia.edu