The Vault
11 min · Maison memorandum
Mirrors the archive entry for Opal — Play-of-color physics, hydration discipline.
Physics of play-of-color
Precious opal consists of silica spheres whose regularity creates diffraction. Brightness, pattern coverage, body tone, and viewing angle behavior define face-up beauty. Laboratories may confirm natural versus assembled opal and note treatments such as sugar–acid or smoking when evidence exists.
Pattern and body-tone language
Harlequin and rare broad-flash patterns on dark body tones command apex pricing when brightness is high. Milky potch layers, directional color, and dead zones under tilt break continuity for institutional buyers. We document pattern behavior on video under controlled light, not only stills.
Stability and care
Hydration and crazing risk make opal a humidity-aware asset class. Long-term storage and wear protocols differ from corundum or diamond. That stewardship burden belongs in the underwriting memo — especially for large matrix pieces or thin-top shells.
Market depth
Liquidity is narrower than for corundum but passionate at the top. We favor conservative cutting, transparent treatment status, and sellers who understand crazing history. Certificates anchor authenticity; condition anchors sleep.