Halcyonite

Halcyonite is a mineral found throughout the Ravel, but it is especially abundant on Ystraka. A yellowish derivative of corundum, halcyonite contains too many impurities, especially titanium, to be valued as a gemstone. However, with much of the Ystrak population weighing several hundreds of tons, its durability made it quite valuable to stonemasons, with the not-insignificant traces of titanium lending a degree of tensile strength it may not otherwise have.   Acquisition of halcyonite was the primary motivator for the Bersarthian and Tewani empires' conquests in Ages long past; even in the modern era it is highly prized. Synthetic equivalents are commonly fabricated but the process of doing so is prohibitively expensive for large-scale projects.