Phosphosiderite has lavender skin and selago hair. Her hair is unkempt, comes to a point in the back, covers her right eyes, and comes down to her knees. She has four eyes, four arms, a small nose, plump lips, and prominent fangs.
Phosphosiderite wore a sleeveless layered navy, bright violet, and light blue tunic with a rounded neckline. She also wore dark violet tights with light violet toes that had star-shaped cutouts in the knees.
She wore a sleeveless light blue tunic with a high neckline which featured a dark violet waist and bottom. She wore darker violet tights with torn star shapes in the knees, tucked into violet boots with lighter violet toes.
This is the only regeneration where she had pink eyes instead. Phosphosiderite wore a violet tunic similar to Amethyst's, with a darker violet piece underneath that had a triangular cutout to display her gemstones. She wore dark violet tights with star-shaped cutouts in the knees, tucked into short, light violet boots.
Phosphosiderite wears a white and dark violet tunic with triangular cutouts at the bottom, which creates a torn look. She wears a violet bracer with a white star and a white bracer with a violet star on her upper arms. She wears darker violet tights with lighter violet star shapes on the knees, tucked into darker violet boots with lighter violet tops.
Phosphosiderite is described as goofy and enjoys having fun, but knows when it goes too far. Phosphosiderite combines Ice's stubbornness with Amethyst's recklessness into a bit well wild personality.
Phosphosiderite possesses standard Gem abilities, bubbling, shapeshifting, fusion, regeneration, agelessness, and superhuman strength/durability.