there is no lime stone in this rock. the average pH of the soil in the area where we got the river rock is 5.6 I know this becase someone charted the pH in this area when they did a study of the whole Island. that is why I find it strange.

but they have done clothes washing in the area and it could be some pH is caused by the soaps used along the river by the people living along it. but I did a check of the pH of the water in the river it is 7