The occurrence of granite spheres in a variety of sizes is a unique phenomenon in Costa Rica. The fact that there is absolutely no information about their history or anything known about them at all is as fascinating as the balls themselves.
Anyone who has seen them wonders the same things: who made them, how, why, and when? Archaeologists have determined that none of them shows evidence of having been shaped or water worn. A common belief is that the balls were grave markers because among the items found in grave sites have been the smaller round balls.
The stone balls found in the Diquis Delta range from a few inches to 8 feet in diameter. They are in perfect proportion, are very smooth, and are generally made of the local lava, so their weight runs from a few pounds to over 16 tons. How could the perfect roundness have been achieved by hand crafting, either now or in the distant past? There must have been some sort of machine to aid in their building. And how could they have been moved? Where did the granite come from, since there were no quarries anywhere near where they were found?
It can't be determined just how many of them there are or were because they have been taken away to Europe, moved throughout the country to decorate parks, and they have been blasted to bits by those scavenging for gold. It is possible that they once numbered in the thousands.
Some of the balls which have been found have been exactly identical within an inch to others found near it. It seems from this that there was some rhyme of reason to having made them. Some of them lie in a series with an exactly equal space in between them, and some have postulated that they could have been arranged in a way that matches the planets and/or stars in the galaxy, like some kind of ancient astronomy lesson.
The conditions which the balls are and have been faced with have varied tremendously. For example, the falling of giant tropical trees must have occasionally shattered them. After the trees are burned down, they are also subjected to fire, the heat of the sun, and to rain. Because of the hot weather combined with the chill of the rainy weather, the balls are exposed to heat and cold, and they are deteriorating as a result.
Three of the balls have been found to be made of a hard coquina which is almost like limestone. Coquina is "the result of shell deposits which solidified after beaches had been raised above sea level. Its hardness depends partly on the amount of sand which has been included.
The coquina balls may have come from raised beaches near the mouth of the Diquis River. This implies that they had been rafted for some 20 miles upstream on the main river, then at least for another 10 miles on smaller streams, one of which lies 300 meters east.
The following are some of the observations of S. Lothrop: "The large groups may have had a ritual significance as they were set in formal alignments. Of the 5 largest groups, 3 seemed undisturbed and in their original positions. In each case there was a baseline of 3, 4, or 5 balls. Two of these lines ran due north and south (magnetic). The third lay east 10 degrees south. All three groups had additional balls flanking the main line in such a fashion that three balls formed a triangle. With this assemblage, various lines of sight were created which may be of astronomical and therefore of ritual significance." 1
Isolated specimens are known from Olmec sites in the state of Vera Cruz in Mexico, and at Zaculeu in the Guatemalan highlands, stone balls have been reported.
One ball had a diameter of 7 feet and an estimated weight of 13 and a half tons. It's not the largest specimen observed, but is the largest one to have been accurately measured." 2
There doesn't seem to be any practical use for these granite spheres, so they must have some sort of ritual significance. Perhaps like the moai statues on Easter Island, the reason for their mystical presence will never be known for sure, but they must have had some magical purpose.
