| An example of a normal|
"weak" Star Seed
A Star Seed, introduced in the fifth and final season, consisted of a very small glittering sphere enveloped in a transparent crystal. When a human was hit by the golden energy blasts produced by Sailor Galaxia's bracelets, a flower appeared above their head or in front of their chest and opened to reveal the Star Seed. Every single person in the galaxy possessed one, but there were two kinds: those belonging to ordinary people, and those belonging to Sailor Senshi. Common people had "weak" Star Seeds which turned black right after being forcefully exposed, and a person whose Star Seed had turned black became a Phage. Those belonging to Senshi had a permanent shine, and were called "true" Star Seeds, or, in the manga, Sailor Crystals. Each planetary body in the galaxy was represented by its own Star Seed, and the Sailor Senshi of that planet was its carrier. If a Senshi's Star Seed was taken out of their body, the Senshi disappeared, which was equivalent to dying. However, a Senshi could continue to exist without their Star Seed as long as they wore Sailor Galaxia's bracelets. If a Star Seed was retrieved, the Senshi could be revived in physical form.
Shape and Color
| An example of a "true" Star Seed:|
The majority of Star Seeds had a hexagonal crystal shape and transparency, but not all looked the same. The Star Seeds of the Inner and Outer Senshi all had the same hexagonal dipyramid shape, but the color of their Star Seed corresponded to their planet color; for example, Sailor Galaxia's was pink and Mamoru's was golden. Usagi's Star Seed appeared to be the Silver Crystal. In the anime, Galaxia's Star Seed was special and seemed to have attained a level of sentience; at various times it took the form of a human child (Chibi Chibi), a sword (the Fuuin no Ken), and a bright pink butterfly, but it also had the common appearance of a Star Seed.
- In the manga, the Golden Crystal in Mamoru's body was exactly like the Silver Crystal in Usagi's. Some fans speculated that the Golden Crystal and Mamoru's Star Seed were the same thing, since both of them were golden and appeared from Mamoru's body. The shape, however, was a little different and the Golden Crystal was not transparent when deactivated.
- There appeared to be a kind of hierarchy between the Star Seeds which was determined by the level of purity. In episode 199, Sailor Galaxia said, referring to the Silver Crystal: "This is undoubtedly the Moon Princess' Star Seed, the most brilliant shine in the galaxy." The fact that Chibi Chibi reached Usagi out of billions of people in the world seemed to prove that.