The Blue Rose (青い薔薇, Aoi Bara) is the prized jewel of the royal family of Sauville. It was lost among many of Sauville's riches in the First World War, and was more recently retrieved in the black market.
The Blue Rose is a large gemstone crafted from the rare blue diamond and has the shape of a rose with many petals. It consists of five levels, with the first four having five "petals" and the last a round shape.
The diamond has an astounding size, enough to cover one's palm.
The Blue Rose belonged to the royal family of Sauville, who also integrates the gemstone into the kingdom's coat-of-arms. The diamond is kept in the security of the Royal Palace in Saubrème, but amidst the chaos of World War I it was stolen and was never recovered.
Police soon receive information in the whereabouts of the Blue Rose, when Kazuya Kujo discovers the diamond by accident inside Jeantan Department Store in 1924, ten years after the war. Although initially discounted as misguided information, Inspector Grevil de Blois soon heeded Kazuya's suspicions about the Blue Rose's location, and a operation was soon initiated.
It soon turns out that the Blue Rose is in the possession of Garnier, the owner of Jeantan Department Store, which also acts as part of the black market. The diamond was among various jewels and works of art that were being secretly auctioned.
After the arrest of Garnier, the Blue Rose is returned to the Royal Palace.
- The "Blue Rose" is also Queen Coco Rose's pet name.