In Too Short To Ride we learned several things about Peridot, the most spectacular being that she can bend metal.

Yes, metal, it’s not telekinesis. It may not have been clear if Steven said metal or mental, but he goes on to list her ability to take the lids off of jars and remove staples. Furthermore, the rings peridot manipulated afterwards made an obvious clinking noise when three of them struck each other in mid air earlier in the episode.

Peridot being able to manipulate metal is a big step forward in her growth as a warrior of the crystal gems, but it’s even more important due to who she’s living with

I’ve spoken a few times about Lapis’s waterbending and whether it or her wings are her weapon. A consistent issue with Lapis and her potential fusions is the fact that nether of these potential weapons seems capable of fusing with that of any other gem.

Now that we know Peridot has metal manipulation as her power however, we finally have something to work with

This is ferrofluid.

Easily made by mixing toner and water, ferrofluid is strange metallic colloid (a mix of two states of matter like a foam, aerosol or emulsion) that forms conical structures in response to magnetic fields.

Whatever fusion Peridot or Lapis have in the future (and come on, you know they will have one) I predict that Ferrofluid is going to be their weapon of choice