Potassium & explosives missing refractive indices

This has come up a occasionally in discussions but amazingly hasn't been formally reported. For fluids lacking indices (eg. RP-1) it doesn't seem to be an issue given the way the game appears to handle them abstractly and it's mainly just for the visual plume. I could consider potassium a priority as it can be used for armour and module shells (even if that's a terrible idea).

Full list:
- Potassium
- Nitrocellulose
- TNT
- PETN