as you can see I was refering Gem in game as Dust type in RWBY. Here is some infomation I was plan to make them.

From wikia we have 8 types of dust as following ;
- Main dust
Air - Green
Fire - Red
Water - Blue
Earth - Yellow

- Secondary
Lighting - ?
Ice - Air(Green) + Water(Blue)
Steam - Fire(red) + Water(Blue)
Gravity - ?

while we have only 6 type of gems.

here is my plan

Air : cast a cyclone like weather pain did. while increase attack speed or walk speed on active.

Fire : as of now we can ignite with melee and cast fire ball.

Water : shield-like that Weiss use? Is that even water or air. I don't know. and waterproof on equip? or just scrap it.

Earth : no idea. cause AOE damage on melee maybe. or scrop it since she never use one.

Lighting : never use and not different from fire it will be just another range dmg that ignite.

Ice : problaby do the same fucntion as Fire, but to acquired by crafting from Green + Blue gem
seem to be hard to get early in game.

Steam : nope

Gravity : nope

if you have suggestion or I miss something from the series please mention that. it would help complete this mod.