A method for manufacturing a mineral-based porous granular material includes providing a starting material of at least 70 weight % of a micaceous arkose rock material. The starting material is in a granular form having at least 50 volume % with a mean diameter of between about 0. 060 mm and about 0. 65 mm. The method includes placing the starting material into a bed on a support surface, placing the support surface containing the bed of the starting material into a kiln, and subjecting the bed of starting material within the kiln to a basic processing temperature of between about 1100° C . and about 1300° C . for a basic processing temperature processing time selected to transform at least 40 volume % of micaceous components in the micaceous arkose material into feldspar, and to evolve at least 30 volume % of metal sulfides within the feldspar from the feldspar as metallic oxides.