Is the blue carbuncle real in 'The Adventure of the Blue Carbuncle'?

Answer 1

This is a typical Conan Doyle enigma. The word carbuncle now is generally used in the medical field to describe a type of puss-filled infection under the skin. The carbuncle gemstone from that time is most generally attributed as a red garnet because the word carbuncle means red in gemology. Garnet stones could be almost any color except blue until the first one was found in the 1990s (a century after 'The Adventure of the Blue Carbuncle' was published) while they still have not been found in China. The chemical elements that make the sapphire blue, titanium and iron, make the garnet black, but the chemical element that makes the newly discovered garnets blue is vanadium.

In related notes, there is not, nor ever was, a British noblewoman titled the Countess of Morcar while there is no Amoy River in China, but Amoy is the former name of an island city on China's east coast today known as Xiamen.