Skyglass

This remarkable crystal seems to be imbued with the power of wind. It is slightly opaque with a green color similar to mint. It is surprisingly light for being solid crystal. Remarkably sturdy as well. It doesn't chip or shatter easily.
Utilized in a variety of ways for a myriad of purposes. With a certain process and/or engine it is able to make airships fly. The wind energy it produces propels the ship in an almost perpetual system. It can also be used to power the ship through a different process. It is a highly sought-after resource. The business of buying and selling Skyglass comprises a large chunk of the markets, both legal and not.
The Confederacy has instituted laws in their territories that limit the size and potency of the Skyglass a person can by. This limit is decided by occupation, class, citizenship, relations, and personal status. They have also standardized and restricted the type of engines a citizen can purchase. Sellers are required by law to submit reports on their sales to the Confederacy.
It is speculated that the crystal can hold energy near indefinitely if not used. It is also theorized that it is the high amounts of energy stored within that make the material sensitive and highly volatile to work with. It can explode if a person doesn't (or perhaps does) know what they're doing.
Because of it's great importance to society and mysterious qualities, eventually a religion was formed around this material, Keepers of the Crystals. It is not coincidence that those countries and organizations with access to Skyglass are the most powerful.
The Lost Kingdom was a major source of this material. They had large deposits all over the kingdom. They utilized their resources and knowledge, to create the first working airship.
Tools made of a special material/compound must be use to excavate it.
Skyglass first started appearing shortly before the Cataclysm, that created the world as people know it today (e.g. floating landmasses, evolved flora and fauna, etc.). Research is still being conducted as to the creation of Skyglass, how to artificially make or mimic its effects, and if it is possible to recharge it.

Type

Ore/Mineral