PB3 — The Lower Boundary of the Pigeon-Blood Range in Trade Use
PB3 — The Lower Boundary of the Pigeon-Blood Range in Trade Use
Rubies that qualify for pigeon-blood discussion but show visible zoning, lower fluorescence, or a stronger purplish modifier
PB3 is dealer shorthand for the lower boundary of the pigeon-blood ruby range — stones that some laboratories will accept as pigeon-blood-grade and some will reject, exhibiting the basic red colour signature but with reductions in saturation, fluorescence, transparency, or clean appearance that place them at the margin of the qualifying population. The term sits below PB2 and PB1 in the trade's informal three-tier stratification of pigeon-blood stones and is used principally in Bangkok and Hong Kong wholesale circles for price-setting purposes.
Where PB3 sits
The pigeon-blood comment issued by Gübelin Gem Lab, SSEF, Lotus Gemology, and AGL is binary: a stone either reaches the laboratory's threshold or it does not. PB3 designations apply to stones at or near that threshold — stones that may receive a pigeon-blood comment from one laboratory and a vivid-red comment from another. Visible colour zoning, a stronger purplish or pinkish modifier, lower transparency, or weaker red fluorescence are the typical features that move a stone toward PB3 territory rather than PB2.
Origin and treatment status remain the dominant price drivers within PB3 as in the higher tiers. Heated Mozambique stones in PB3 grade are the most commonly encountered material in the wholesale trade; heated Mogok and Mong Hsu PB3 stones are less common and price at a meaningful premium. Unheated PB3 stones from any origin are scarce and trade at significant premiums above heated counterparts.
Trade use
PB3 stones often serve as the entry point into the pigeon-blood market for buyers who want a laboratory-supported pigeon-blood designation but cannot reach PB2 or PB1 budgets. Buyers in this tier should be especially careful about laboratory selection: a pigeon-blood comment from a less rigorous laboratory adds little to the stone's market value, while a comment from one of the canonical Asian or European houses moves the stone into the documented pigeon-blood inventory of the trade.
Limitations
The PB3 term is informal and varies by dealer. Where a stone is offered as PB3, buyers should request the underlying laboratory report and verify that the colour, fluorescence, and treatment comments support the pigeon-blood discussion the dealer is relying on.