Laboratory practice
12 min · Maison memorandum
The grid is a snapshot, not a film
Proportions, finish, and clarity diagrams on colorless diamond reports summarize geometry and inclusion positions at one moment. They do not replace observation of fluorescence behavior, tilt extinction, or subtle transparency differences under varied lighting. Pair every grid with hands-on cinema and, when warranted, supplemental studies such as advanced imaging or updated scans after recutting.
Comments, not only the headline grade
Inscription notes, additional comments, and clarity characteristic sketches often carry disproportionate information relative to a single grade token. For colored stones, origin probability, treatment indications, and stability notes frequently live outside the largest type on the page. Institutional buyers build internal memos from these lines first, then fold in face-up beauty.
Type IIa as scientific classification
Type IIa diamonds contain negligible nitrogen in forms that define Type I chemistry. They can be exceptionally transparent colorless performers or host unusual optical behaviors. The designation is not a beauty grade — it is a scientific family label that sometimes correlates with auction storytelling. It becomes dangerous when treated as a standalone investment thesis without cut quality, fluorescence, and provenance context.
Cross-reading and contradiction
When major laboratories disagree on origin or treatment probability, the task is to map methodology sensitivity and evidence weight — not to split the difference. Some splits reflect genuine scientific limits; others reveal sample handling or document age. Maison practice archives PDFs, tracks recut events, and revisits opinions when material changes occur. Certificates are contracts of language; we hold them to that standard.