Lapis Lazuli is a water Gem and member of the Blue Diamond court. She was loyal to Homeworld until she ended up trapped inside of a mirror down on Earth during the early years of the Gem War, being discovered by the Crystal Gems. she remain trapped in the mirror for thousands of years until she was released by Steven Universe, and became a Crystal Gem herself.
Lapis Lazuli is a slim, medium-sized Gem, standing just under Pearl's height. She has cyan blue skin, and her hair a coblat, chin-length, and styled similarly to Pearls, but with longer bangs and her fringe covering her whole forehead. She wore a backless crop top with the Blue Diamond symbol on it, and a flowing dress that goes down to knee-length. On the upper part of her back is where her Gemstone is, which is shaped like a water droplet. Prior to being healed, her eyes were replaced with reflections of a mirror, but once healed they turned back to royal navy blue.
As of Season 6, her appearance has changed somewhat from the original: her dress and crop top now connect, with the dress now shorter than it was before. Her upper half is now light silver, with a blue band with a star at the center of her stomach. Her new reformation also added a blue scarf around her neck.
For a Gem who's life is full of trauma, Lapis Lazuli is shown to be surprisingly cheerful and friendly towards others, more prominently towards those that aided her in her life, such as Steven Universe for not only freeing her from her mirror, but also healing her Gemstone when the others didn't do so. While showing to trust the Mane Six right away, Lapis wasn't so willing to trust the Crystal Gems at first, but started to warm up to them after some time, and encouragement from Steven. As a water Gem, Lapis has developed a fascination with water, and extensive knowledge of underwater life. Her care towards others does sometimes get her to making some questionable decisions, such as not willing to fight Jasper during her attack on Earth, and lying to Blue Diamond about Pink Diamond's shattering, and informing her (and Yellow Diamond by extension), that she had simply gone missing, not wanting to hurt either Diamond.
With both her time trapped in a mirror, and her time as Malachite, Lapis has developed a strong guilt in herself, though it doesn't show up very often and covered up by her good nature. In times when it does, she behaves much more withdrawn and more humble, this behavior more prominent in Malachite as she went as far as to isolate herself from the world, blaming herself for what happened and pushing others away. While she has grown up from isolation, she still has shown some resentment on the subject. While still recovering from Malachite, she has fully recovered from her mirror traumatic experience, as shown in the My Little Universe: Mindwarp special.
A notable feature of Lapis Lazuli, she has a very high power and control over water. It's unclear as to the limits of this ability, able to store a decent amount of water into her Gemstone, and able to use said water as either enhancements to her water wings, or converting it in combat. However, she has shown to strain if holding too much water with her water wings alone.
She is considered the piloting flyer of the Crystal Gems, very maneuverable in flying. She can fly fast enough to keep up with Rainbow Dash in a race, and as her water wings are more broad, she can cut corners faster than most other flying animals can at high speed.