I found an unglazed Emile Henry baking stone today at a local discount retailer (for $20). While it claims to be a newer "flame" rectangular baking stone, it baffles me because all the baking stones by Emile Henry appear to be glazed. Is this truly a deliberate mistake? In that case, I was wondering it worth keeping and using as normal stoneware, or if I should exchange it for a "correct" (black) version? Thanks in advance for your help.