What was a spacestone?
Most Mages would never be able to lay their eyes upon the true appearance of the legendary spacestone!
Most books that described the spacestone only contained a simple description of its importance as the core material of interplanar, ultra-long-distance teleportation arrays.
This description wasn't incorrect, but it wasn't entirely accurate either.
The construction of an interplanar teleportation array was still possible without a spacestone. However, an Mage's tower would have to serve as a spatial coordinate for the spatial transfer. A large number of magical crystals would have to be exhausted during every transfer as well.
All of this meant that an interplanar teleportation array without a spacestone consumed a large amount of money and resources. There was also a long period of time before the infrastructure was built.