Granite blisters are formed through a geological process known as exfoliation. This happens when the layers of granite, much like an onion, begin to peel off due to the release of pressure, changes in temperature, and chemical weathering.
To put this in simple terms: Granite is created deep inside the Earth where it’s hot and under much pressure. As time goes by, erosion wears away the rocks above stuff, decreasing the pressure on the granite.
Pressure Release: When the granite feels less pressure, it starts to expand a little. This creates stress in the outer layers, which causes cracks and peels that run parallel to the surface.
Temperature Changes: The heating and cooling every day cause the surface of the granite to expand and contract. This weakens the bonds over time and leads to flaking.
Chemical Weathering: Water and other chemicals infiltrate the cracks, weakening the granite and helping to separate the layers. Doming Effect: If such processes happen on a large scale, then granite can develop domelike or rounded structures. The peeling layers have an appearance similar to blisters, for which the term was coined. Granite blisters are typical in any area of exposed granite