The AGL Prestige Report
The AGL Prestige Report
American Gemological Laboratories' fullest coloured-stone document
The Prestige report is the most comprehensive document issued by American Gemological Laboratories of New York, one of the small group of laboratories whose coloured-stone reports trade at premium in the international market. AGL was founded by Cap Beesley in 1977 and is now led by Christopher Smith, who served previously at GIA and Gübelin. The Prestige report sits above AGL's standard reports in scope and analytical depth, and is most often commissioned for stones of significant size, rarity, or value where origin and treatment determination are decisive.
What the Prestige report contains
A Prestige report includes the standard descriptive elements common to all reputable coloured-stone documents: weight, dimensions, shape and cutting style, transparency, species and variety identification, and a colour description following AGL's proprietary ColorScan system, which evaluates hue, tone, and saturation against reference benchmarks. To this baseline, the Prestige report adds detailed treatment determination, origin opinion where supportable, and AGL's quality grading commentary on cut, clarity type, and overall finish.
Treatment determination is the section most often relied upon. AGL describes treatment status using the AGTA-coordinated terminology — none detected, heat only, heat with residues, clarity enhancement, diffusion, irradiation, and so on — with explanatory notes on the methods used and the confidence of the determination. For corundum, the report addresses both the question of heat and the question of more aggressive treatments such as beryllium diffusion or lead-glass filling.
Origin opinion, the third pillar, is rendered when the laboratory's analytical and microscopic data support a confident attribution. Like Gübelin and SSEF, AGL is conservative in origin attribution and will decline to issue an origin opinion where the data permit multiple interpretations.
Methodology
AGL's analytical suite includes standard gemmological observation, magnification under a range of light sources, refractive index, specific gravity, ultraviolet response, infrared spectroscopy, ultraviolet-visible-near-infrared spectroscopy, and energy-dispersive X-ray fluorescence for elemental analysis. The combination is sufficient for routine treatment determination and, for the species and varieties where origin is determinable, for confident origin opinion.
The Prestige report's distinguishing feature is the level of narrative commentary and the inclusion of photo-documentation of internal features. Where a competing laboratory might issue a tabular result, the Prestige report explains its conclusion in language an experienced trade professional or sophisticated client can follow.
Position in the market
For coloured stones with provenance significance — fine ruby, sapphire, emerald, alexandrite, Paraíba tourmaline — AGL is one of the laboratories whose reports the trade considers authoritative, alongside Gübelin Gem Lab in Lucerne, SSEF in Basel, Lotus Gemology in Bangkok, and GIA in its origin-issuing capacity. AGL is the leading American option for clients and dealers who prefer a New York-based laboratory and who value the depth of narrative reporting in the Prestige format.
When to commission a Prestige report
The Prestige report is most worthwhile for stones above approximately five carats in commercial varieties, or for any stone where the origin or treatment status will materially affect value. For small-to-medium stones in conventional commercial cuts, AGL's standard reports may be more economical and equally informative. For diamonds, AGL is not the appropriate laboratory; GIA, AGS, and HRD are the standard references.
In the trade
When clients ask which laboratory to use for a fine coloured stone, the answer depends on the stone and the destination market. For Burmese ruby and Kashmir sapphire bound for auction, Gübelin and SSEF reports often carry the most weight. For paraíba and for stones being sold within the American trade, AGL Prestige reports are routinely the document of choice. The trade's respect for AGL is built on more than four decades of consistent practice and the laboratory's reputation for declining to issue an opinion when the data do not support one.