What issue can arise if quarry tile is not sealed properly?

When quarry tile is not sealed properly, one significant issue that can arise is permanent damage from grout. Quarry tile is often porous and can absorb moisture, which includes not just water but also grout materials. If the tile is not sealed, the grout may infiltrate the tile and cause stains or damage that can't be easily removed. This absorption can lead to discoloration or even degradation of the tile's surface, potentially leading to costly repair work or replacement. Proper sealing serves as a protective barrier that prevents such materials from penetrating the tile, preserving its appearance and structural integrity over time.