Final answer:
Gilderoy Lockhart is associated with extravagant robes, whose shades aren't specifically mentioned in the book but may include turquoise, forget-me-not blue, aquamarine, and peacock blue.
Step-by-step explanation:
The character Gilderoy Lockhart from "Harry Potter and the Chamber of Secrets" is known for wearing flamboyant and colorful robes. While the exact shades of blue that Lockhart wears in the book are not specified, some often associated shades with his character could include turquoise, forget-me-not blue, aquamarine, and peacock blue. These colors reflect his extravagant and attention-seeking personality.