PB3 is the lowest of the three pigeon blood tiers in Lotus Gemology's colour grade for ruby. A PB3 stone has cleared the laboratory's threshold for the pigeon blood designation but sits at the entry point of the category. It is, in commercial terms, a pigeon blood stone that has reached the bar but is unlikely to be confused with the apex stones at PB1.

Where the line falls

The pigeon blood threshold is a deliberate construction. Lotus has chosen to publish a structured scale rather than treating pigeon blood as a single pass-fail call, recognising that the historical use of the term covered a range of vivid reds rather than a single colour point. PB3 captures the stones at the qualifying edge of that range - vivid red, with the right hue and tone window - while leaving the rare absolute apex of the category exclusive to PB1.

Pricing implications

A PB3 designation still earns the pigeon blood premium, which is itself substantial - frequently a multiple of the price of a non-pigeon-blood ruby of comparable size, clarity, and treatment status. But PB3 stones trade at discounts to PB2, and at deeper discounts to PB1, with the differentials widening for unheated Burmese material at the highest sizes.

Why the structured scale matters

The structured PB1/PB2/PB3 scale gives both buyer and seller a vocabulary for distinguishing between pigeon blood stones rather than pretending all pigeon blood material is equivalent. For the trade it has been a useful reform: it has limited the dilution of the pigeon blood term that occurred during the 2010s ruby boom, by giving the top end of the scale a name distinct from material that simply scrapes the lower threshold.