What rock are traditional molcajetes carved from?

Traditional molcajetes are carved from basalt. This dark volcanic rock is typically vesicular, meaning it contains small cavities formed as gas escaped from cooling lava.

A molcajete is a Mesoamerican stone mortar, traditionally paired with a hand-held pestle called a tejolote. Pre-Hispanic cultures, including the Aztec and Maya, used related stone tools to grind maize, chiles, spices, and other foods. The rough basalt surface is especially useful for crushing ingredients and producing the characteristic texture of salsa or guacamole.

New basalt molcajetes usually need to be broken in before cooking. Repeatedly grinding uncooked rice helps remove loose stone particles that could otherwise make food gritty. Modern imitations may use pressed concrete mixed with volcanic-rock particles, so not every inexpensive molcajete-shaped vessel is solid basalt.