Okay, for those of you who are starting to scratch your heads and say "what's up with all the fake minerals?" I have written this post to explain how I see everything meshing together in my little VSF universe.
Firstup: good old hydrium. I may need to change the name, as it was originally created by an author named Kenneth Oppel. I took the name because I liked it, and have credited him several times for it, but it is still technically a copyright infringement if I ever publish any of this. At this point, I think I am safe under the realm of amateur fanfic. So look for a name change to something like helios, or monoionic hydrogen, or something, in the relatively near future. Anyway, what it is, is a lifting gas, several times more efficient than hydrogen and non-flammable. So, way better than hydrogen, and responsible for the motley assortment of Zeppelins and other lighter-than-air vehicles floating in the skies of my games.
IMVU (In My Victorian Universe), hydrium is produced biologically. It can be found on all three of the inhabited planets. On Earth, only certain subterranean fungi produce it, so it is found in underground deposits. On Mars, large flying creatures produce hydrium and store it in bladders within their bodies, allowing them to fly. As yet, I have made no specific mention of hydrium on Venus, though I intend it to exist there.
I posted on hydrium last year a few times, especially in regards to the deathrays. I also mentioned it as appearing in plants, causing floating trees. This is an idea I have discarded as too similar to Space 1889's liftwood trees.
Handwavium is the energy soure that has opened the aether to Earthly explorations. By bathing handwavium crystals in an alkaline solution, a rather intense heat is created chemically, without using oxygen. The handwavium gives off a green glow as the reaction takes place. The handwavium acts as a catalyst, and is not consumed in the reaction.
Handwavium reactors boil water to steam for use in steam engines, turbines and generators. The process is remarkably similar to a nuclear power plant: large pipes with water in them pass through the reactor vessel, heating the water via conduction (if I remember my heat transfer types correctly). The resultant steam is then put to work. Large reactors can provide sufficient power for generating electricity for entire small towns or factories.
Handwavium is rare and widely scattered on Earth. Deposits of the green crystals have been found in England, Ireland, Egypt, Nevada, South Africa, Siberia, Manchuria, and the Andes mountains, among other places. It can also be found on both Mars and Venus in similar deposits. There is an apparent correlation to ancient civilizations' ruins and handwavium deposits. I will probably develop more along those lines in the future.
IMVU, there are two methods of generating better lighter-than-air lift than is actually possible in our known universe: hydrium and unobtainite.
Unobtainite is a blue, slightly translucent crystal. It is entirely unremarkable until an electric charge is passed through it. Once it is exposed to 'galvanic forces,' unobtainite begins to rise upward. The more voltage is passed through, the stronger the anti-gravitational force becomes. Thus, by increasing or decreasing the voltage by a simple rheostat, a vessel equipped with unobtainite lift will gain or lose altitude.
Unobtainite has several advantages over hydrium. The most important is that it takes far less volume of unobtanite to generate the same lift, given sufficient electrical current. It can thus be carried inside a vesssel, behind protective shielding, whereas hydrium requires a large gasbag which, for all intents and purposes, is unarmored. Unobtainite vessels are swifter, with far less drag than hydrium zeppelins. Also, piloting an unobtainite vessel is much easier to do, and requires fewer crewmembers.
Unobtainite is found on Earth in small quantities. The largest deposit so far has been located in the central African highlands. It is much more common on Mars, where Martian scientists discovered its amazing properties millenia ago, at the height of the Martian civilization. To date, no unobtainite has been found on Venus at all.
Please note that, other than the name hydrium, as explained above, I do claim copyright on the ideas outlined above. Feel free to use the ideas in your own personal and private games, so long as you grant credit appropriately. Please do not print or publish these ideas in any form or format without my permission.