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Uluru (Northern Territory, Australia)
This is the most famous rock in Australia, and probably also the world. Uluṟu (previously known as Ayers Rock) is a ~ 550 million year old isolated rock (inselberg) of arkosic sandstone. It has actually been tilted on its side by 90° since its formation way-back-when. Uluṟu is really a huge rock that continues for possibly 5 to 6 km below the surface, sort of like an iceberg for comparison. You can see the sub-vertical layers and ribs that have been accentuated by years and years of erosion in the Aussie outback. The actual colour of Uluṟu is grey sandstone. However, it has turned to orange-red on the outer surface due to oxidization of the iron (i.e., rusting) in the sandstone overtime.
