One of the attractions of Chamarel aside from its forests and food is the seven-coloured earth, a unique geological feature showing earth in red, brown, green, yellow, blue, purple and violet tones forming exposed ‘dunes’ amidst dense forests. The area is only 7,500 m2 and these land formations result from the action of water and rain, creating these dunes described as “gently convex slopes and rounded interfluves” in between which the rainwater flows.
 D. Newsome and C.P. Johnson “Potential Geotourism and the Prospect of Raising Awareness About Geoheritage and Environment on Mauritius”, Geoheritage 5, no.1 (2013): 1-19
The origin of this exposed and wavy multi-coloured soil is debated but a few hypotheses have been put forward. The geological features have often been described as resulting from the erosion of volcanic ash rock, known as tuff. Some geologists dispute this claim, saying that it confuses erosion with weathering or alteration of the rock in place. Instead, it is likely that weathering of basalt itself as opposed to tuff is the process responsible for creating the formations. Although the site is considered “natural”, geologists are now discovering that much of the gullying found around the world – as shown in the gentle slopes in the site – is a result of modification of the land surface by human activity. A resulting hypothesis is that this specific area was cleared by humans to grow crops or for other reasons and soon after a severe storm resulted into the complete removal of the top soil.
Erosion of basalt results in clay. The climatic conditions of the area – hot and humid - have led to further transformation of the soil into ferralitic soil through hydrolysis (the chemical breakdown of a compound through reaction with water). Thus, the chemical weathering of basalt has led to two dominating elements in the soil, namely iron and aluminium resulting in red/anthracite and blue/purple colours and tones respectively. It has been said that even when one mixes all colour sections of the soil together, they would eventually separate.
 H.C. Sheth, C.P. Johnson and C.D. Ollier “The seven-couloured earth of Chamarel, Mauritius”, Journal of African Earth Sciences 57, no.1-2 (2010): 169-173