State gem

The sapphire was named the official state gem for Queensland in August 1985.

About the sapphire gemstone

The sapphire gemstone, a variety of the mineral corundum, was originally discovered in central Queensland in the early 1870s. It continues to be found in the central and northern parts of the state.

As found in nature, a typical corundum is very dark in colour. With tinges of blue, green or brown it is nearly opaque, although the transparent varieties display a wide range of colours, from yellow and gold to purple.

The name sapphire (Aluminium Oxide) was traditionally used for clear, blue corundum stones. Nowadays, except for the pink varieties which are called ruby, it is common to refer to stones of all colours as sapphires.

The pink to red colour of ruby stems from its chromium content, whereas the sapphire's blue results from its titanium content. Yellow and green sapphires contain variable amounts of ferrous and ferric iron.

The hardness of the sapphire is second only to that of the diamond.