It is unknown what Silena definitely looks like, as her introductions keep stating different Цвета of hair and eyes. In The Demigod Files, it сказал(-а) that her hair was black, and her eyes Шоколад brown. In The Last Olympian, her eyes were blue and her hair was brown. In The Ultimate Guide, her eyes were blue and her hair was blonde. In all descriptions, she is descibed slim. However, it is always stated that she is a very beautiful girl who everyone stares at. Since she is a daughter of Aphrodite she may have the ability to alter her physical appearances или she simply gets bored of her apperance (possibly her ADHD) and changes them.
According to Riordan wiki Silena is described as having brown eyes and black hair in the demigod files and blue eyes and brown hair in the last Olympian. Yet another hair color is дана to her in "the ultimate guide" where she is described having blonde hair. Even though she is дана many different descriptions, most people see Silena with black или brown hair and blue eyes. Hope this helps!