Rajasthan is endowed with a continuous geological sequence of rocks from the oldest Archaean Metamorphites, represented by Bhilwara Super Group (more than 2,500 million years old) to sub-recent alluvium and wind blown sand. The western and north-western parts of young unconsolidated deposits including the blown sand of the Thar Desert (Marusthal) of western Rajasthan. The remaining area exposes wide variety of hard rocks which include various types of metamorphic schists, quartrzites, marbles and gneisses of Pre-Cambrian age with associated acid and basic intrusive rocks. The sedimentaries include the rocks of Aravalli Super Group, Delhi Super Group, upper Precambrian Vindhyan Super group and of Cambrian to Jurassic, Cretaceous and Tertiary ages. The south-eastern extremity of the state is occupied by a pile of basaltic flows of Deccan Traps of Cretaceous age. Several mineral deposits of economic importance occur in association with the above rock units.

The geological sequence of the state in highly varied and complex, revealing the co-existence of the most ancient rocks of Pre-Cambrian age and the most recent alluvium as well as wind-blown sand.

The Aravallis, one of the most ancient mountains in the world, have the oldest granitic and gneissic rocks at their base, overlain by the rocks of the Aravalli Super group, Delhi Super group, the Vindhyan Super group and younger rocks. These rocks are highly metamorphosed at certain places and show rich occurrences of minerals of great commercial importance.

The characteristic feature of the geology of Rajasthan is the presence of several groups of rocks belonging to Archaean and Pre-Cambrian ages. They form the Aravalli mountain system which runs across the state from the north of Delhi in the north-east to the Gulf of Cambay in the south-west. The central part of the Aravalli ranges is occupied by a great synlinorium composed of Aravalli and Delhi rocks. Because of the thin deposits of sand in this region, the rock exposures are good but in the west and south-west, they are often engulfed in sandy alluvium and desert sands.