Catawiki is a Netherlands-based online auction platform founded in 2008, originally as a collectibles catalogue before pivoting to live weekly auctions across dozens of specialist categories. Within the gem and jewellery trade, it has established itself as one of the more significant digital sales channels for mid-market coloured gemstones, mineral specimens, and finished jewellery, drawing a predominantly European buyer base with growing international participation. Its distinguishing feature within the crowded online auction landscape is a mandatory pre-listing expert review process, which differentiates it from open-marketplace models such as eBay and positions it closer — in curatorial intent, if not in price tier — to the specialist departments of the established auction houses.

History and Structure

Catawiki was founded in Assen, the Netherlands, by René Schoenmakers and Marco Jansen. The platform began as a tool for cataloguing personal collections of comics and stamps before its founders recognised the commercial potential of a curated, category-specific auction model. By the early 2010s it had expanded into coins, classic cars, wine, art, and — of particular relevance to the gemmological trade — gems, minerals, and jewellery. The company is headquartered in Amsterdam and operates across more than thirty countries, with its interface available in numerous European languages, which has been central to its success in reaching buyers across France, Germany, Spain, Italy, and the Benelux region.

The platform operates on a consignment model: sellers submit lots, which are then reviewed by Catawiki's in-house category experts before being accepted, rejected, or returned for additional documentation. Accepted lots are listed in weekly themed auctions — for instance, dedicated sales of coloured gemstones, of diamond jewellery, or of mineral and fossil specimens — each running for a defined period, typically several days, with a closing sequence designed to prevent last-second sniping. Catawiki charges sellers a commission on the hammer price; buyers pay a buyer's premium in addition to the lot price, a structure broadly analogous to traditional auction houses.

The Expert Review Process

The curatorial layer is Catawiki's most consequential point of difference from open peer-to-peer marketplaces. Before any gem or jewellery lot is listed, it must pass review by one of the platform's employed or contracted specialists. These experts assess submitted photographs, seller-provided descriptions, and any accompanying laboratory reports, and they may request additional documentation or decline lots that cannot be adequately verified. This process does not replicate the rigour of a full gemmological laboratory examination — Catawiki is not itself a testing laboratory and does not issue grading reports — but it does impose a baseline standard of plausibility and presentation that filters out the most egregious misrepresentations.

For coloured gemstones specifically, the platform encourages — and in some categories effectively requires — the submission of recognised laboratory reports from institutions such as the Gemmological Institute of America (GIA), Gübelin Gem Lab, SSEF Swiss Gemmological Institute, or Lotus Gemology, among others. Lots accompanied by credible third-party reports command measurably stronger bidding, as buyers gain confidence in species identification, weight, and, where relevant, origin and treatment disclosure. The presence or absence of a laboratory report remains one of the most reliable predictors of final hammer price on the platform.

Coloured Gemstones on Catawiki

The gem and jewellery categories on Catawiki span a wide range of material, from commercial-grade parcels of mixed sapphires or garnets to individual collector-quality stones with full laboratory documentation. The platform's sweet spot is broadly the mid-market: stones and jewellery pieces that are too modest in value to attract the attention of Christie's or Sotheby's specialist gem sales, yet too significant — or too in need of a curated context — for a general peer-to-peer listing. Rough and polished mineral specimens, including gem-quality crystals of tourmaline, beryl, and spinel, also appear regularly and attract a collector audience distinct from the jewellery trade.

Sapphires, rubies, emeralds, and alexandrites with credible provenance or laboratory confirmation of geographic origin tend to perform particularly well, as the platform's European buyer base includes a substantial number of informed private collectors who understand the significance of, for example, an unheated Ceylon sapphire certificate or a Mozambique ruby report. Coloured stone parcels — multiple stones of matched colour or cut, sold as a single lot — represent another category where Catawiki offers a practical sales channel for dealers and cutters seeking direct-to-consumer reach without the overhead of a retail operation.

Market Position and Limitations

Catawiki occupies a distinct position in the hierarchy of gem and jewellery sales channels. It sits above open marketplaces in terms of curatorial oversight and buyer confidence, but below the major international auction houses in terms of price realisation for top-quality material, marketing reach among ultra-high-net-worth collectors, and the reputational weight that attaches to a Christie's or Bonhams provenance. For sellers of mid-market material, this positioning is often precisely appropriate: the platform delivers competitive bidding from a large and engaged buyer pool without the consignment thresholds or lengthy sale cycles associated with the major houses.

Limitations are real and worth noting. The expert review, while valuable, is not infallible, and buyers should exercise the same due diligence they would apply to any auction purchase — examining photographs carefully, reading descriptions critically, and requesting clarification from sellers where descriptions are ambiguous. Return policies and dispute resolution are governed by Catawiki's own terms rather than by the long-established practices of the traditional auction world, and buyers outside the European Union should be attentive to import duties and VAT implications that can materially affect the landed cost of a purchase.

The platform's reserve price structure and starting bid conventions also differ from traditional auction practice. Many lots carry no reserve, which can produce strong results for sellers when competitive bidding develops, but can equally result in below-expectation realisations for material that fails to attract early interest. Sellers of significant stones are advised to set reserves accordingly and to ensure that laboratory documentation and photography are of sufficient quality to generate early bidder confidence.

Catawiki in the Broader Online Gem Trade

The growth of Catawiki as a gem sales channel reflects a broader structural shift in the coloured stone market over the past decade. Direct-to-consumer digital sales have compressed traditional distribution chains, allowing cutters, small dealers, and specialist retailers to reach end buyers without the intermediary layers — wholesaler, importer, retailer — that historically characterised the trade. Platforms that combine curatorial oversight with genuine auction mechanics occupy a particularly useful niche in this landscape, offering buyers a degree of confidence that open marketplaces cannot provide while offering sellers access to a buyer pool that individual retail websites struggle to build independently.

For the gem trade, Catawiki's weekly auction rhythm also creates a useful price-discovery function. Hammer prices on well-documented lots — particularly for species and origins where market data is otherwise sparse — provide a running record of what informed private buyers will actually pay, a form of market intelligence that complements the price guides and dealer-to-dealer benchmarks that have traditionally shaped the trade's pricing conventions.

Further Reading

• Gems & Gemology — GIA's peer-reviewed quarterly journal (gia.edu)
• Catawiki Gemstones category (catawiki.com)