Steven Universe Theories

Metals have elemental powers

First I'll start off with Lapis Lazuli. Actual Lapis is made of Pyrite(metal), Calcite(metal), and Sodalite(gem). Calcite and Pyrite are commonly found in water. My theory is that the metals have control over elements. The metal part of Lapis gives her the powerful control over water while the gem part gives her the wings. This also can explain why her eyes were reflective. It could be because she was trapped in a mirror or it could show the metal part of her.

I think the desert glass is Jade. Actual Jade is made of a lot of metals like aluminum, silicon and sodium. Those metals are found in sand. Nanafua said before, "did you know when sand is super heated it turns to glass." That might've been talking about the desert glass(Jade). The desert glass or Jade has extreme power over the element of sand. Jade and Lapis can both be made by flame fusion.

Rose in "we need to talk" had the power to give life as we've seen in "Lars and the cool kids" but the moss that turned into flowers was not sentient. Steven gave life to the melons but they did not follow his every command. I think that Bismuth has nature powers which is supported by the inside of Lion's mane. Bismuth combined with Rose would make it to where instead of One person completely controlling plants that can't move on their own (Bismuth) and one that can make them to where they can move on their own but can not control them (Rose Diamond) should make one that can do both. Rose Quartz could make living sentient plants that can fight on their own because she has the power of nature from Bismuth and the life giving power from Rose Diamond.

I think that there was a war between the metals before that made homeworld have to create more gems with bits of metals and gems. This only works with gems with exceptionally strong elemental powers.