Red Sandstone

Hardness: 6-7 on Mohs scale; Color: reddish-brown to orange; Luster: dull/earthy; Crystal structure: clastic (primarily quartz grains); Cleavage: none; Specific gravity: 2.2-2.8.

Formed through the accumulation and lithification of sand-sized mineral particles or rock fragments. The red color is due to the presence of iron oxide (hematite) which acts as a cementing agent. These often form in desert or fluvial environments and can date from billions of years to relatively recent geological eras.

Used widely in construction for building facades, paving, and decorative garden stones. Historically significant as a building material for temples, cathedrals, and monuments.

Red sandstone is famous for creating the landscape of the American Southwest, including the Grand Canyon. The 'Old Red Sandstone' is a world-renowned suite of rocks in the UK that helped geologists first understand the Devonian period.

Identify by its gritty, sandpaper-like feel and visible sand grains. It is commonly found in sedimentary basins and arid regions. Collectors should look for unique cross-bedding layers or trace fossils within the specimen.