Pyrite

Pyrite are both equippable items and NPCs in Magical Starsign and Magical Vacation. They are said to gain conciousness at 12mm.

Biology
Pyrite are silver cubes with no limbs. Their main method of movement seems to consist of one rocking back and forth. Each one has a face that resembles a three-prong outlet, with an orange glow coming from inside.

Behavior
Pyrite are very eccentric but vary greatly in other behavioral regards. Each pyrite seems to want nothing more than to join the player on his/her journey, even if that only means being sold for quick cash.

Super Smash Bros. Brawl
A Pyrite appears in the game as a trophy. Like other Magical Vacation series trophies, Magical Vacation is omitted in their appearances.

Trivia

 * Pyrites score 6 on the Moh's Scale of Mineral Hardness.

Name Origin
Pyrite is the name of a mineral, sometimes called iron pyrite.

Their individual names seem to reflect their personality/what they say to the player.