The agate mines in the Sierra Mountain range of Aguascalientes supply a vast variety of fire agate material - the largest in the world. From golden fire to rainbows of colored fire, encased in a quartz-chalcedony nodule embedded throughout the mine walls in the mountains. The mines are found at different locations above the town of Calvillo, some require a certain agility to climb up the cliff faces to enter. Some are too dangerous to enter because of large ceiling boulders that are poised to fall, floods from the seasonal rains have also collapsed some mines making them impossible to enter, while other mines are drained of any quality agate material from over-mining from the 1970's.

You will notice that some of the mines listed here have more than one name, this has happened over the years because a mine might close, then a new vein would appear after torrential rains sometimes, leading to new discoveries that actually are just a different area of the same mine. But, the miners have now given a new name to the mine and only the oldtimers will use the mine's original name. Or sometimes to try and keep a find quiet, a miner will use a different name, only to have it catch on and everybody starts to use it. As we hear of new of different names for the Calvillo mines we will continually add them to the list.