Coober Pedy is without a doubt one of the most unique outback destinations in Australia. Set in a stark arid landscape often compared to Mars, this outback mining town where many people live underground is the source of most of the world's precious opal production.

Coober Pedy is located about 850 kilometres north of Adelaide in remote outback Australia. The name Coober Pedy comes from a local indigenous language, Kupa meaning 'white man' and Piti meaning 'hole', and translates as 'white fellas hole in the ground', reflecting the fact that Coober Pedy is the Opal Capital of Australia and the world. It also reflects the fact many residents live in homes excavated underground due to the extreme climatic conditions of the area.

Opal mining commenced in Coober Pedy in 1915 and continues today. In that time the outback town has evolved in to one of the most unique places in Australia and perhaps the world. A cosmopolitan town of 3,500 inhabitants from over 45 different nationalities, it is today a relaxed and friendly town characterised by cultural tolerance, diversity and acceptance.

Apart from opal production, Coober Pedy is known for its unique style of underground living. Visitors can find a range of underground accommodation in addition to above ground accommodation for those who prefer it. There are many often luxurious underground homes to explore in addition to underground shops, museums, art galleries and mines.

Coober Pedy enjoys a typical semi-desert climate. Between April and October the weather is pleasant, with mild daytime temperatures of 16 to 20 C but cold desert nights. From November to March, summer temperatures are hot and range from 35 to 45 C, and occasionally reach as high as 50 C. No wonder the locals prefer to live in the relative comfort of underground homes! Annual rainfall is unpredictable and minimal at an average of around 175 millimetres.

Opal was first found on the surface at Coober Pedy in 1915, while the New Colorado Prospecting Syndicate consisting of Jim Hutchison, his son William Hutchison, P Winch and M McKenzie were searching unsuccessfully for gold south in the area. This was on the 1st of February 1915, and the first opal claim was pegged eight days later. Originally known as the Stuart Range Opal Field (after early explorer John McDouall Stuart, the first European explorer to traverse the area in 1858), this name was changed to Coober Pedy in 1920.

Following the completion of the Trans Continental Railway in 1917, a number of construction workers moved on to Coober Pedy and were followed by soldiers returning from World War 1. Conditions were harsh, with water and provisions having to be transported great distances and under trying conditions. The introduction of large underground water tanks improved the situation only marginally, as the water entitlement was only 60 litres per week.

Today Coober Pedy's water is pumped from an underground source 24 kilometres north of the town. The water is treated by reverse osmosis before entering the town water supply system, en expensive process resulting in water costs of $5 per 1,000 litres. Nevertheless, the water is of excellent quality and people should have no reservations about drinking it!

Opal prices fell dramatically and production almost came to a standstill during the Great Depression of the 1930's. As has been typical of Coober Pedy's history of cyclic boom and bust periods over the decades, an Aboriginal woman named Tottie Bryant made a sensational opal find in 1946 which initiated a new rush to the Coober Pedy opal fields. Mining activity grew rapidly during the 1960s as many new European migrants arrivd seeking their fortunes. Since then, opal mining has develop into a multi million dollar industry and Coober Pedy has grown into a modern outback mining town.

Opal is a type of silica similar to quartz, but it contains water within its mineral structure. Precious opal typically contains 6% to 10% water. Opal occurs in many varieties, including precious opal and potch. In precious opal, brilliant colours are created by the diffraction of white light by silica spheres and voids within the opal structure, similar to a prism effect. The colour range of a precious opal is determined by the size and spacing of the silica spheres. Smaller spheres produce blue opal only, while larger spheres produce red opal. Red opal can also display the entire spectrum of colours. Opal colour is influenced by the angle of the light falling on it, and can change or disappear as the stone is rotated. Potch opal has silica spheres which are too small and irregular to produce colour.

If you are interested in purchasing precious opal, be aware that to date attempts to establish guidelines for setting opal values have been largely unsuccessful. This is because of the infinite variation in colour pattern found in opals. The most important factors determining the price of opal are the background colour (black opal being more valuable than clear or crystal opal, which in turn is more valuable than white or milky opal), the dominant fire colour (red-fire opal being more valuable than a green opal, which in turn is more valuable than blue opal), and the colour pattern (harlequin opal with patches of colour is more valuable than pinfire opal with speckled colour). Be aware also that there is a significant difference between the value of uncut opal and that of a cut and polished stone.