Arizona pyrope garnet is called ant hill garnet because ants bring up the smaller crystals from below ground and deposit them in the ant hill when building or remodeling. The ants encounter the garnets while excavating their underground passages, haul them to the surface and discard them.
The rain washes the garnets clean and moves them down the flank of the anthill where they can accumulate in large numbers. This concentrates the little gems and makes them easy for people to collect.
Ant hill garnets occur in a remote section of the Navajo Nation in Arizona. During the 1800's Navajos in this locale used the water-worn and rounded ant Hill garnet crystals as bullets.
Ant hill garnets are recognized as possessing the finest bright ruby-red color of the garnet family. The typical anthill garnet is a tiny stone - almost always less than one carat when cut into a cabochon or faceted stone. The ants are smart enough to excavate around larger stones rather than haul them to the surface.