Every guide on Vintagesieraden.nl leans on verifiable sources. We prefer, in this order: primary hallmark registers of national assay offices, museum collection pages (Rijksmuseum, V&A, Metropolitan Museum, Boijmans, MAK Wien), peer-reviewed literature on decorative arts and gemmology, and standard reference works published by professional bodies (RTG, HRD, GIA, WOSTEP).
What we accept as a source
- Primary registers and official archives of assay offices and patent offices.
- Publicly accessible museum collection records with an inventory number.
- Peer-reviewed articles and monographs in art history, gemmology and horology.
- Guild and trade-body publications where they add practical recognition detail.
What we do not accept
- Auction descriptions or dealer listings as sole evidence for period or attribution.
- Anonymous forum posts, social media claims and AI-generated summaries.
- Provenance claims without an accompanying laboratory report or archival trace.
How we cite
Where a claim depends on a specific record, we link to the source itself — the museum's own collection page or the register entry — rather than to a summary about it. Indicative market prices are marked as indicative. Uncertain dates are given as ranges. When sources conflict, we say so.
Last reviewed: juli 2026.