On one of my frequent weekly visits to Canoa, I made contact with people around the zocalo or main square. On this day, two little girls started talking to me and invited me to the backyard of their home where their grandmother was on her knees preparing corn masa with the traditional volcanic stone mano or grinding stone, and metate or grinding slab. Years of hard work are written on her face and on her hands. She isn't kneeling on a flat surface, by the way, but one of many irregular stones. Try doing that for any length of time and then lifting the long stone mano she uses to grind the corn.
Volcanic stones imbue food ground with them with a very special flavor that cannot be matched by machine blended food. Try a tortilla made from volcanic stone ground corn and your taste buds will thank you.