The molcajete is the Mexican version of a mortar, and its accompanying tejolote is the pestle. Use one to grind spices and grains, to mix salsas and guacamole, and even to serve. And when not in use, we think molcajetes have a beautiful, functional aesthetic that's perfect for displaying in the kitchen:However, not all molcajetes are made equal. There is a cheap version out there that is a combination of concrete and basalt. Concrete is full of harmful chemicals that you definitely don't want in contact with food. Pure basalt molcajetes will be very dark in color (practically black) and porous. Basalt is harder than the imitation and will hold up to the grinding that you plan to put it through.
Three sources for authentic basalt molcajetes (they aren't the cheapest you'll find, but they are the real thing):
Do you have a time-proven molcajete in your home? Where did you get it?
Related: Quick Tip: Season Your Molcajete With Rice
(Images: as linked above)