The Floating Magical Item
The Floating Magical Item is fairly common in fantasy settings, especially in handheld gaming. It isn't as readily available as the power of flight is often seen as breaking game balance, or out of place in low to mid level magic settings. This is quite a shame as there are a number of magic items that float and move about without relying on thrust, aerodynamics, buoyancy, or other means of lift. Such things include floating stones, levitating swords, flying carpets, magic brooms and so forth.
A fairly common application, the Lesser Supernatetium is a spell of levitation applied to a small object, allowing it to move with the spellcaster, or whomever the item is bonded to, without them carrying it. These objects are small, not heavy, and are not suited for serving as platforms, lifts, or transportation devices for anything other than tiny creatures like mice, faeries, and such.
A common application of Lesser Supernatetium is the creation of floating relics and charms. These items are created as boosters for magic users, adding to the magic potency, or functioning as reservoirs of mana allowing them to cast more spells. These relics range from mundane but useful things like lanterns to religious symbols, to artistic representations of the magic user's specialities. A powerful necromancer might have a magically charged skull with black adamant eye stones that she uses as a spell booster and focus for powerful magics. It is useful, but a pain to try and carry. A trailblazer mage might have a lantern that floats nearby, providing light, but allowing him to keep both of his hands free for spells, or gesturing while speaking.
Limits: the Lesser Supernatetium is limited to no more than 10-12 pounds of weight it can move about. The lighter the object, the longer the magic works before requiring a recharge. A twelve pound relic might only be brought out when it is needed, but a crystal cut in the likeness of a flower, a few ounces in weight, could easily drift along for an entire day without issue.
The slightly less common Intermedium Supernatetium is predictably, a stronger version of the lesser spell. It can levitate up to fifty to sixty pounds, operating under the same general guidelines presented above. It can move and carry things, but not more than 50% of it's own weight. Anything more will cause it to rapidly sink to the ground.
There are several applications of the intermedium supernatetium, large relics, wondrous household objects, and object d'art. Large relics might be stone cuttings, large ornate works of metal and glass, or even things as macabre as a mummy turned into a power object, or the skull of a large beast. Household wondrous objects include floating tables and platforms that can be easily moved by porters or unseen servants. Objects d'art are wondrous works of beauty or spectacle that are not intended for combat or other PC exploits. Rather, they are works of art blending magic, craftsmanship, and beautiful (or horrible) things.
The Greater Supernatetium is a well known spell, placed on witches' broomsticks, magic carpets, and other sundry items giving them the power to move around. This allows the item enchanted thusly to carry several hundred pounds of weight, or to be a relic of impressive size, such as a small statue, or elaborate man sized panoply. These items tend to be powerful and gamebreaking if misused, or allowed to be abused.
The method of controlling a greater floating object would be to give it charges that replenish over time, and the more strenuous the activity, the more quickly it's power is depleted. This could be countered by a magic user powering the object with their own potency, but this is sacrificing spell power for basic locomotion. Wise magic users will be judicious in how often they embark on a long journey on their flying carpet or magic cloud, versus traveling via mundane methods, but keeping their spells ready.
The Supernatetium Submission is a Building Block submission, not one intended to stand on it's own. But we want more examples, we want more fluff, we want more more more. More is coming, I have been working on this for a while and have struggled on how to approach it. In the future there are going to be relics and such that will link back to this as a foundation submission for people who want to see the supporting structure under it. Be patient. Also, feel free to create your own floating items and use this sub as a the 'This is how it works' link instead of spending two paragraphs explaining how mages used magic to make things float.