Aries: Ruby/Jasper

Ruby:

Jasper:

Taurus: Bismuth

Bismuth: 

Gemini: Steven/Peridot

Steven: 

Peridot:

Cancer: Aquamarine

Leo: Yellow Diamond

Virgo: Peridot/Pearl

Peridot:

Pearl:

Libra: Rose Quartz

Rose: 

Scorpio: Sapphire

Sapphire:

Sagittarius: Topaz (Unfused)

Topaz:

Capricorn: Blue Diamond

Blue Diamond:

Aquarius: Lapis/Garnet

Lapis:

Garnet:

Pisces: Amethyst

Amethyst:

*Note: I'm going to actual birthstones on Steven Universe. These are just based on their personalities. :3