The Pearl gene can be confusing genetically, since it only has an effect on Mink based rats (and even then, it’s not as predictable as you’d hope it would be). Therefore, the Russian pearl variety is also described as Dove Pearl or Russian Cinnamon Pearl, since it is a combination of Russian blue, Pearl, and a Mink gene too.
Genetics: Russian blue combined with Pearl and either Mink or American Mink (aammrbrbPepe or aaamamrbrbPepe)
NFRS standard: To be a mid silver, with a creamish undercolour. The majority of hairs to be pearl tipped with grey, interspersed with occasional grey hairs. The top coat must be short and thick with a slight metallic sheen. Belly fur to be a pale creamy grey. Foot colour pale grey. Eyes black.