THE ENIGMATIC STONE BALLS

Stone balls are a widely known. They are explained:

by geologists as a natural phenomenon, which is true for some balls,

by archaeologists as man made, which is true for some others,

by mythology and legends as very ancient balls carved by the gods,

but no explanation so far can explain the whole phenomenon.

DIFFERENCE BETWEEN NATURAL AND MAN-MADE STONE BALLS

1.    Geologists explain the formation of spherulites and megaspherulites by the crystallization of vitreous (glassy) rhyolitic volcanic material, after it has been erupted as pyroclastic flows and while these deposits cooled to create either vitrophyre or welded ash flow tuff.

2.    Concretions: These natural stone balls, which are found within sedimentary strata have nothing to do with volcanoes. Instead, these stone balls are concretions, which formed naturally by the local cementation of sediments into a spherical mass by the precipitation of either calcite, silica, siderite, dolomite or other minerals within the sediments enclosing them.

In sharp contrast to the stone balls formed by cristallyzation or concretion, stone balls of Costa Rica consist of granodiorite and are clearly of man-made origin.