The Vault
10 min · Maison memorandum
Mirrors the archive entry for Spinel — Vivid reds and cobalt blues, collector renaissance.
Optics and clarity culture
Spinel’s high refractive index and lack of double refraction yield crisp luster that reads ‘clean’ even when inclusions are present under magnification. Clarity expectations differ by hue family: vivid reds and cobalt blues often trade with more tolerance for crystal clouds than colorless diamond desks would permit.
Cobalt commentary and blues
For blue spinels, laboratory commentary on cobalt-related absorption can separate premium cobalt blues from iron-gray blues with similar photography. That distinction is price-moving; we read spectral appendices and comments with the same care applied to copper lines on tourmaline.
Marble-hosted provenance
Many top reds and some blues derive from marble-related geologies with characteristic inclusion suites. Origin opinions from major European and Asian laboratories carry weight at auction when they align with microscopic character and trace chemistry.
Investment framing
Institutional interest has risen as origin science matured. Liquidity remains thinner than for ruby or sapphire, but masterpiece spinels with repeat opinions and transparent treatment status can outperform on a rarity-adjusted basis. We underwrite to conservative clarity of enhancement and stable provenance.