Sapphie is a Cavalier King Charles Spaniel dog with lemon yellow fur and cornflower blue ears. Her Jewel Eyes are made out of blue sapphires. For her attire, she wears a light pink and light blue flower garland on her head and a white pearl necklace with a blue treble clef note-shaped sapphire jewel attached around her neck. Sapphie's Jewel Charm is egg-shaped and colored blue. It is embedded with a dark blue star-shaped sapphire and four small round dark blue sapphires surrounding it. It is also decorated with white-gold trimmings. According to the official website, Sapphie is quiet, smart, kind and loves to look at the outside world from the windowsill.

In the anime, Sapphie is friendly, calm and understanding of everyone's feelings, Sapphie knows how kind her friends are, in both Jewel Land and on Earth. She is very supportive towards Aoi Arisugawa and Sara, her partners in the first and second series, but is also supportive towards her other partners as well. Sapphie is also the most responsible and most studious, taking place in charge to see her plans come to life. As the Jewelpet of Friendship, Sapphie's magic can allow humans to befriend anyone with ease. In her official setting in the franchise, Sapphie's power also includes gaining intelligence and calm judgement, as well as the ability to see beauty. Despite her personality, Sapphie has the highest magic ranking of all Jewelpets: "Crystal Class", since all of her magic is considered successful when casted. Though a few Jewelpets have this class, Sapphie is considered to be the most studious of the three and also has good skills in inventing and creating experiments. Usually, she relies mainly on both science and magic in all of her studies. Sapphie can also wield a miniaturized version of the Jewel Stick for her magic or with Ruby and Garnet, to summon other Jewelpets from Jewel Land. In Jewelpet Kira☆Deco!, she wields a Jewel Pod, which she will consider decorating it with a Philosopher's Stone.