Final answer:
Marguerite's physical appearance is described as thin and colorless, while her personality is portrayed as elusive and mysterious.
Step-by-step explanation:
In the given passage, the physical appearance and personality of Marguerite are described indirectly. The narrator describes her as 'thin and colorless', suggesting a lack of distinctive features. The narrator also mentions that Marguerite never said or did anything remarkable, except for one memorable action. Despite these descriptions, the narrator recalls her eyes as wonderful. Overall, Marguerite is portrayed as a shadowy figure, elusive and mysterious.