The molcajete, a hefty mortar and pestle typically crafted from a hunk of volcanic rock, is one of the oldest and most essential tools in kitchens across Mexico and Texas alike. These must-have devices have been used for centuries to grind spices, chiles, seeds, nuts and more. Examples of molcajetes — the term is derived from the Nahuatl word "molcaxitl" — have been found in ancient Aztec and Mayan archeological sites, according to the University of Texas at San Antonio's Institute of Texan Cultures Thanks to their rustic looks, dramatic heft and dominating presence, molcajetes are also a fixture at restaurants across San Antonio.