Every major, world-recognized city has its unique landmarks and
features. Sydney, Australia’s oldest city (settled in 1788) and
largest (more than 3.5 million people), and soon to host the
2000 Summer Olympics, is no exception. It has its beautiful
harbour and famous bridge, its Opera House and golden beaches,
but it also has some unique and characteristic rock formations.
The Hawkesbury Sandstone, named after the Hawkesbury River just
north of Sydney, dominates the landscape within a 100 km (60
mile) radius of downtown Sydney. It is a flat-lying layer of
sandstone, some 20,000 sq. km (7,700 sq. miles) in area and up
to 250 metres (820 feet) thick.1 Dominated by grains of the
mineral quartz2 (which is chemically very similar to window
glass, and harder than a steel file), the sandstone is a hard,
durable rock which forms prominent cliffs, such as at the
entrance to Sydney Harbour and along the nearby coastline.
Despite the widespread, spectacular exposures of the Hawkesbury
Sandstone, there is a long history