Housekishou Richard-shi no Nazo Kantei

When Seigi Nakata rescued a handsome young jewelry appraiser from a group of drunken assailants, he got more than he bargained for! The appraiser is Richard Ranasinghe de Vulpian, a brilliant and mysterious British jewelry expert. Seigi hires him to appraise a family heirloom…and that is just the beginning. Together, they unlock the secret messages hidden in the hearts of precious stones–and those who possess them.

(Source: Seven Seas Entertainment)