The utensil I'd like to describe is the sil-pata, a flat grinding stone that's been used in kitchens in Bangladesh for centuries. I'm a thirty-year-old secondary school teacher in Sylhet, and we still have one in our kitchen, although it was my grandmother's originally.
It has two parts, both made of stone. The sil is the base, a heavy flat slab about the size of a large chopping board, with a rough surface that's been chipped in tiny patterns so it can grip food. The pata is a smaller cylinder-shaped stone, a bit like a rolling pin, that you hold in both hands.
To use it, you sit on the floor or crouch next to it and put whatever you want to grind on the slab, things like turmeric, chillies, garlic, ginger, mustard seeds or lentils that have been soaked. Then you press the pata down and roll or rock it backwards and forwards until everything becomes a smooth paste. A little water helps. It's hard work, and grinding enough spice for a big family meal can take twenty minutes.
You might wonder why people still bother when electric grinders are so cheap. For a lot of families, especially older people, the answer is taste. Grinding by hand releases the oils slowly and doesn't heat the spices, so the flavour is much stronger. My mother insists that fish curry made with stone-ground mustard is completely different. It's also about tradition. In many homes, the sil-pata is part of a bride's household goods, passed down through generations. That said, I'll admit that on weekday evenings even my mother uses the blender.