The area around Dumfries is very famous for its red sandstone out of which most of the buildings locally are constructed from. This sandstone is of Permian age and has been extensively quarried in the area. However most of this quarried rock is red in colour whereas the material with the rings in is a very pale yellow/white colour. It is unfortunately only ever found as loose erratic boulders in the bed of the river or in its small beaches and has never been found in situ as massive bedrock.

The rings can measure up to 4 centimetres in diameter where the ferruginous content is high. The sandstones around Dumfries formed when arid sandy conditions prevailed and the sandstone thus has an aeolian origin. Presumably this staining consists of colour zones formed of oxides of iron, which has resulted from the oxidation of grains of possibly pyrite that has been scattered throughout the matrix of the sandstone. It appears to be fairly stable even when exposed to water so maybe a more permanent reaction has taken place as part of its formation.