Not all of the round rocks at Roundrock are round rocks.
The round rocks formed over millions of years in a mineral-rich soup of rock and water from strata deep within the earth. They subsequently eroded free from the soft stone around them and collected in my forest. (Okay, not only in my forest.)
As has been asked, though, why are they round? Or put another way, why aren’t they not round? Wouldn’t gravity have played some part in their shape?
The fact of the matter is that we do find many oddly shaped rocks in our woods. I’ve included photos of them on occasion, and today’s photo is a curious example of a non-round, round rock. (I suspect this one might be a fusion of two round rocks that were forming near each other in the mineral soup.) We have many that are elongated or flattened. Some are teardrop shaped. Some are ovoid. Some even look like fat hot dogs. Most of these irregulars are broken, and we can only guess at what shape they had taken when whole.
According to the geologist who told me all about the meteor impact and the ensuing 350 million years of history, these rocks formed around a nucleus of blue-green shale. When we examine some of the broken round rocks, we often do see the shard of shale at the center (though sometimes there doesn’t seem to be any core substance). I suppose that depending on the size and shape of the shard, the rock that accretes around it might follow that general direction and not be perfectly spherical by the time Pablo finds it in the current era.
Did gravity play a part in their shape? I suspect not. When I say that the stones were suspended in the mineral-rich soup, I may be giving the wrong impression. This was not liquid. From what I understand, this “soup” was more like a very loose, crumbly limestone, so the round rocks would be “liberated” from the distorting force of gravity as they pirated minerals and transformed the stone around them into their own substance. If you know how hail forms, or a pearl, you can get an idea of how these round rocks grew.
So not all of the round rocks at Roundrock are round rocks. But our eyes are drawn to the ones with the more pleasing shape, and as the Dread Pirate Roberts observed, they call out for being collected. Thus it is the round, round rocks that get all of the attention.