Naturally formed giant balls of stone are a rare phenomenon in most parts of the world, but not on a mountain top near Ahulaluco, 75 kilometers west of Guadalajara, where hundreds of them lie nestled in a bed of soft volcanic ash. It’s even said that these are the largest megaspherulites (their scientific name) in the world, for which reason I decided to go measure a few of the biggest I could find.
“At the same time,” I told my Mexican relatives, “I can check out all the improvements made by the Jalisco Secretariat of Culture to facilitate the access of tourists to this extraordinary site.”
Fortunately, local highways to Ameca and Teuchitlán have been upgraded, allowing us to drive to the place from Guadalajara in only one hour. Now, I had been told that the six-kilometer-long access road to the Stones would be “paved,” but in fact, it turned out to be just another steep dirt road with several bad patches, requiring four-wheel drive for safe negotiating. Sad to say, there is no sign telling you what you are getting into and only after you are on it do you discover that this “road” is only wide enough for one car along much of its length, affording you very few opportunities to change your mind and turn around.
As we rose in altitude, we passed two well-built, truly awesome ziplines (one is 330 meters long) and a very narrow swinging bridge for pedestrians with no safety feature whatsoever to keep spooked walkers from falling to their deaths. No one was using any of these, even though it was a Sunday afternoon, and I could only think that if the cost of these extreme-sport gizmos had been applied to constructing a proper access road, (They had a budget of ten million pesos) hundreds of people might be visiting the Great Stone Balls today instead of the twenty or so we noticed.
These folks, by the way, had either parked or abandoned their cars out of desperation at various points along the ever-steeper, ever rockier road and, in fact, only one vehicle had actually made it all the way to the parking spot, where the Stone Balls first begin to appear.
To me, these Piedras Bolas are just as impressive now as the first time I gazed upon them some 30 years ago, after a long, hard hike of several hours, during which our guide (a ten-year-old local boy) managed to get us good and lost for a while. Surely the first human beings who saw the Stones must have scratched their heads, concocting theories about where they came from and how they were made. Even today you can hear stories about how the “old ones” sculpted each of them by hand, but when USGS geologist Robert L. Smith visited the site for NatGeo and the Smithsonian in 1968, he concluded that each ball was formed by a simple process of crystallization around “starter crystals” of rhyolite inside a pyroclastic flow which had begun to cool.
Universidad de Guadalajara (UDG) researchers came up with a similar theory, which they expounded in a book in 2007 but – surprisingly – a prominent sign at the Piedras Bola site “explains” that the balls flew up out of a volcano, high into the sky and just happened to fall into a bed of soft ashes which preserved their round shape: a theory which has been rejected by just about everybody.
I was curious whether I could locate a large Ball which the UDG publication claims to be “9.6 meters in diameter.” Now, a while ago I discovered that these researchers had been using the word diameter while they actually meant circumference and, indeed, we were able to measure one of the biggest balls with a fiberglass tape and found it to be nine meters in circumference and, therefore, 2.9 meters in diameter. This Ball is located at N20 39.266 W104 03.468 and I propose that it be duly honored as “The World’s Biggest Megaspherulite” until proven otherwise, or until somebody wanders up the hill and finds a larger one.
Our voyage down from the Piedras was scarier than on the way up, as we encountered several parts of the road covered with gravel, causing the car to slip and slide as if we were driving on ice, something you don’t want to experience when there’s a 200-meter drop at the edge of the road and no guard rail. Luckily, we didn’t find a single upward moving vehicle during our return, so there was no need for us to put the car into reverse in order to reach one of the very few wide spots along the way, a scenario fit for a nightmare.
The Piedras Bola are still well worth a visit, but I suggest you either walk all the way up or go there in a Jeep.
How to get there
From the Guadalajara Periférico, take Highway 15 (towards Nogales and Tepic) 25 kilometers to Highway 70 which heads southwest towards Ameca. Go about 18 kilometers and turn right onto the road heading for Teuchitlán and Ahualulco. From this turnoff, it’s 27 kilometers to Ahualulco. Just past the town, turn left onto the scenic highway to Ameca, marked by a big Piedras Bola sign. Drive 14.1 kilometers to a small parking area (N20 38.510 W104 01.834) on the left side of the road where there’s another big Bola sign. On the opposite side of the highway you’ll see the cobblestone road heading up to the Piedras, but it’s at such an angle that you can hardly make the turn coming from the direction of Ahualulco. The cobblestones, by the way, soon come to an end and then it’s dirt all the way to the Stone Balls (six kilometers). The drive from Guadalajara takes about one hour and so does the trip up the narrow dirt road, depending on the speed of whatever car you happen to be stuck behind. The Piedras Bola can also be reached from the Lake Chapala area via the Mazetepec-Tala divided highway.