Earthstone stands as tall as the Diamonds, about the same size as Blue Diamond. As a fusion, the structure of her body mixed Connie's thinner features with Steven and Amethyst's thicker ones, making her thicker than Stevonnie, but still thinner than Smoky Quartz. Her skin resembled the color of brownish clay, and her face had Smoky's freckles. Her hair is prominent, and darker in color to mirror Stevonnie, still shaggy like Smoky Quartz. She possesses two gemstones, one on her chest and one on her stomach, matching Smoky Quartz gemstones almost exactly. Her outfit consists of a tank top and shorts matching Steven, her tank top with his patterns, sleeves only shown on her lower arms, with the exception of a purple bra band on her right shoulder.
Earthstone has four arms: the upper pair thicker and more muscular by an inch when comparing to her lower arms. She also has a third eye in the middle of her forehead much like Garnet.
Earthstone shares a sense of protection and care towards her friends similar to the Gems she's fused with. She's more than willing to take on opponents directly, possibly a side shown from Amethyst, though still showed great concern and need to help others, evident from Connie and Steven. These traits are easily shown throughout her appearances.
She forms for the first time within the White Diamond Space Station when White Diamond asked for an opponent to fight in a duel. She was only allowed to fight since she technically was one person. Willing to face her, Earthstone fought White Diamond for a good while, but she got tired after a while and White Diamond knocked her down. Lapis Lazuli saved her from being killed, and she was forced to split when Lapis went berserk on everyone.
When they found Malachite, Earthstone returned again, not willing to fight her and more trying to heal her. She was forced to fight her however, and provided a good distraction as the Mane Six restrained her. Once properly restrained, she tried to heal her, and she had to work fast when Malachite got free, managing to place her healing spit onto her gemstone, and successfully healing Lapis Lazuli.
A trait gained from Steven, Earthstone is shown to successfully heal Gemstones in a similar way, shown when she successfully healed Malachite.