Miss Pope, from Langton Matravers, in Dorset, disappeared on the afternoon of 7 November.
A 19-year-old man remains in custody on suspicion of her murder.
In a statement issued through Dorset Police, Miss Pope’s family said: “If anyone knows where Gaia is we beg you to let us know.
“To Gaia. We all love you forever. We miss you beyond words. We will find you darling girl.
“The thought of seeing the sunshine of your smile again soon keeps us all going and hoping.”