Sandstone is a sedimentary rock formed by the accumulation and cementation of sand particles, which are typically quartz grains. When you examine a sandstone, you can usually see these individual sand grains within the rock, often giving it a gritty or sandy texture.
On the other hand, tuff is an igneous rock formed by the consolidation of volcanic ash and fragments ejected during an explosive volcanic eruption. It is typically composed of tiny rock fragments, glass shards, and mineral crystals. These components of a tuff are usually very fine-grained, and it can be challenging to distinguish individual fragments with the naked eye. As a result, tuff often has a more compact, cohesive, or uniform appearance compared to sandstone.
