Sapphire

"I've never had more than one!-Sapphire"Sapphire is a future-seeing gem who is currently fused with Ruby into Garnet.

Powers
Cryokinesis-Sapphire has cryokinesis, the control of ice.

Future vision-Sapphire has the ability to see the most likely outcome of the future.

Ruby
Sapphire and Ruby have been in a relationship for over 5000 years. They are very close, but have had disagreements in the past. During "Hit The Diamond," they flirt for a portion of the episode. They split for a long time upon realizing how Rose had lied to them, and Sapphire yelled at Ruby before leaving. Ruby then came to terms with things and proposed to Sapphire. They are now married and fused again. Sapphire is shown to be impressed by Ruby's unpredictability.

Pearl
Pearl helps Sapphire come to terms with Rose's choices during "Now We're Only Falling Apart." During the events of "The Question," Pearl attempts to comfort Sapphire, but begins crying herself. They are later shown talking over a cup of tea.

Amethyst
Sapphire has not interacted with Amethyst on-screen, but they have very different personalities. Amethyst was confused by Sapphire's violent emotional reaction to Ruby's departure.

Steven
Sapphire would appear to have a caring relationship with Steven, although she does not understand his emotions at times.

Peridot
Sapphire has not been shown interacting with Peridot on-screen.

Lapis Lazuli
In the series "Gem-to-Gem", Sapphire and Lapis create meep morps together and discuss adjusting to the freedom Earth allows. In "Hit The Diamond", Lapis dramatically declares that Ruby and Sapphire are flirting, but seems unfazed by it.

Fusions
When fused with Ruby, they form Garnet.

When fused with Pearl, they form Moonstone.

When fused with Lapis Lazuli, they form Tanzanite.

When fused with Peridot, they form Dioprase.

When fused with Pearl and Ruby, they form Sardonyx.

When fused with Amethyst and Ruby, they form Sugilite.

When fused with Ruby and Peridot, they form Watermelon Tourmaline.

When fused with Ruby and Steven, they form Sunstone 2.0.

When fused with Ruby and Rose Quartz, they form Sunstone.

When fused with Pearl, Amethyst, and Ruby, they form Alexandrite.

When fused with Pearl, Ruby, and Peridot, they form Snowflake Obsidian.