Best of best — abbreviated in the trade as BOB — is an informal but widely recognised designation used by dealers, auction specialists, and collectors to identify gemstones or jewellery that represent the absolute pinnacle of quality within a given species or variety. The term encompasses the convergence of exceptional colour, high clarity, fine cutting, and, where applicable, prestigious provenance. BOB material commands significant premiums over even very fine commercial goods, and stones so described are almost invariably accompanied by certificates from leading gemmological laboratories such as GIA, Gübelin, or SSEF.

Defining Characteristics

No single numerical threshold defines best-of-best status; the designation is holistic and comparative. A BOB ruby, for instance, must satisfy demanding criteria across every quality axis simultaneously: colour in the narrow range described by leading laboratories as pigeon blood, eye-clean to loupe-clean clarity, a cut that maximises brilliance without sacrificing weight unnecessarily, and — for the most coveted examples — a documented origin such as Mogok, Burma. The same logic applies across species: a BOB Kashmir sapphire must exhibit the velvety royal blue associated with that deposit, while a BOB Colombian emerald should display the warm, slightly yellowish green traditionally associated with the Muzo or Coscuez mines.

Critically, all criteria must be met together. A stone with extraordinary colour but significant inclusions, or a flawlessly clean stone in a mediocre colour, does not qualify. The term implies no compromise.

Laboratory Endorsement and Nomenclature

In contemporary trade practice, BOB status is closely tied to laboratory opinion. Certificates from Gübelin Gem Lab, SSEF Swiss Gemmological Institute, or GIA that carry colour-quality descriptors — pigeon blood for ruby, royal blue for sapphire, vivid green for emerald — serve as objective anchors for the designation. Origin determinations (Burma, Kashmir, Colombia, Paraíba) further reinforce BOB claims, since certain localities carry inherent prestige that the market has consistently rewarded. At major auction houses including Christie's, Sotheby's, and Bonhams, lot notes for BOB material routinely cite both the laboratory descriptor and the origin conclusion as co-equal pillars of value.

Use in the Trade

The abbreviation BOB circulates freely at trade fairs — including the Tucson Gem & Mineral Show, the Las Vegas JCK show, and the Bangkok trade week — as well as in dealer-to-dealer correspondence. It functions as a rapid signal that a parcel or individual stone is not merely fine but trophy-grade, warranting serious attention from collectors and estate buyers. The AGTA (American Gem Trade Association) recognises quality-tier language of this kind in its market communications, reflecting the term's broad acceptance across the coloured-stone industry.

Because the designation carries no standardised definition, it is also susceptible to inflation. Experienced buyers treat unsupported BOB claims with appropriate scepticism and rely on laboratory documentation and independent appraisal to verify the assertion. Reputable dealers apply the term conservatively, understanding that overuse erodes its commercial credibility.

Relationship to Pricing

The price differential between fine commercial goods and genuine BOB material can be substantial — often non-linear. Auction records for unheated Burmese rubies with pigeon blood designations, or unheated Kashmir sapphires, illustrate how the convergence of origin, colour grade, and size can push per-carat values to multiples of what a merely very fine stone of the same species would achieve. The rarity of stones satisfying all BOB criteria simultaneously is itself a market force: as deposit yields decline and existing collections consolidate, genuinely trophy-grade material becomes increasingly scarce in the open market.