Ruby has light red skin, dark maroon hair, and is slightly taller than Steven. She wears a violet-red and dark red tank top leaving her arms free, a light red headband around thick, outgrown hair cropped at the neck, mid-thigh length maroon shorts, and pointed violet-red boots. Her gemstone is located on the palm of her left hand, and has a square facet.
She takes on Garnet's strength and courage, while Sapphire embodies Garnet's cool nature and kindness. She seems to put the well-being of Sapphire over all else, as she immediately made sure Sapphire was safe and responded "Who cares?!" when Sapphire asked her if she herself was okay.