The best way to monetize Granite Blocks is to craft Granite Candelabras: Convert to Smooth Granite Blocks at a Work Bench without any loss, then use 5 Smooth Granite Blocks and 3 Torches. Candelabras sell for 3, for a profit of 150 if Torches are purchased, or 270 if crafted. This takes into account the value of the Torches if sold directly.
The real-life counterpart of the granite found in-game is most likely Larvikite, also called "blue pearl granite."
Due to the block dropping from both Granite Golems and Granite Elementals, Granite (and some items made from it) can be considered renewable.
Granite Golems spawned from their respective statue will still drop Granite Blocks, making it an incredibly easy block to obtain.