Honeycomb sandstone

3D Model

This specimen of coarse grained sandstone has a lithic arenite composition and is a great example of honeycomb weathering. Honeycomb weathering can occur due to many factors, but the most common is infusion saline water followed by salt crystallisation. Known as haloclasty, the salt water penetrates rocks like sandstones, primarily through the permeable cement component. When the water subsequently evaporates, salt crystals nucleate, and their growth causes physical breakdown of the weaker cement, thus liberating sand grains. It is very common procees observed along coastal regions. This particlar sample comes from the Newcastle (Australia) coastline where lithic sandstones of the Newcastle Coal Measures crop out along the coast. These particlar sandstones have relatively weak cements composed of clays, iron oxides and lesser silica. Reconstructed model uploaded 2nd February 2021.