Sandstone is a sedimentary rock basically composed of grains of sand. It forms in seas and deserts where sand accumulates and is compacted and cemented together with various naturally occurring materials. The cementing materials can be quite colourful, and may form interesting patterns called Liesegang rings in the resulting stone. Sandstone, being plentiful, relatively soft and easy to cut, has long been popular as a building material. And when the stone saw meets a Liesegang ring, the results can be quite decorative.
I recently visited my Alma Mater, the University of Melbourne. Melbourne is one of the "Sandstone Universities", together with the other older Australian universities, taking this name from their liberal use of sandstone as a building material. I was intending to photograph the Law Building and its justifiably famous and beautiful cloister and quadrangle. The light wasn't right, but not far away something else caught my eye. The building blocks show here are all from a small section of the Old Arts Building, and demonstrate the natural beauty of this ancient building material. While the interior has no doubt been remodeled many time since it was built nearly 100 years ago, the exterior has lost little of its original charm.