Sunstone appears to live by their name; their head resembles a star, which is what the sun is. They also have bright orange skin with normal orange patches, and two sets of arms: one bulky and muscular with the other slender. The smaller pair can often be seen displaying peace signs or shakas, demonstrating their laid-back nature. They wear a pair of dark red shades, covering their eyes, Steven's t-shirt with the sleeves rolled up, Garnet's gloves at the lower arms, Steven's pants as shorts with a red pocket on the left leg, and a blue pocket on the right leg, and Steven's sandals under scarlet leggings.
In many ways, Sunstone resembles a 1980/90s after-school-special cartoon character. They offer self-encouraging platitudes and give helpful advice to children while shouting catchphases like "bungakowa". Overall, they have a chill, laid-back personality even in the heat of battle. Much like Sardonyx, they like to break the fourth wall, encouraging the kids at home not to fight when it can be avoided.