Investigation of Severe Settlements of some Single and Double Storey Houses at Bintulu

Pimple surface of Rock Sample

Most of the failed joints of rock samples have either totally smooth or chaotic irregular surfaces. 
But this failure plane of the Graywacke is rough and is quite uniform.
Perhaps, I am still more used to smooth surfaces, pleasant to see and touch.

Heterogeneous Rock

Sometimes, you can see different constituents within a rock core. This picture shows the dark grey materials surrounded by the lighter rock materials. It shows that Nature seldom comes out with homogeneous materials, especially the sedimentary or metamorphosed rocks.