by Sharon Mascall courtesy of BBC News World Edition

You have to watch your step in Coober Pedy

In 1926, the typist from London made the long journey to Coober Pedy, a remote, South Australian opal mining town halfway between Adelaide and Alice Springs.

"I wish I were a man," she wrote in her memoir Stones of Fire. "I'd love to dig for opals."

Coober Pedy comes from the Aboriginal term kupa piti, meaning "white man in a hole".

"They say diamonds are a girl's best friend, but opal is far more beautiful" Tania Burke, opal miner

Within a few weeks, however, Minnie Berrington was digging alongside the men, pick and shovel in hand, proving that women could go down holes too.

Since the 1920s, hundreds of other women have arrived, hoping to make a living from the precious gem.

Around 95% of the world's opal comes from Australia - and from Coober Pedy in particular. About $1m's worth is pulled out of the ground every year.

Over the centuries, the gem has become part of folklore.

It was worn by Cleopatra, called the "Queen of gems" by Shakespeare, and has been credited with curing eye disease and acting as a good luck charm against poison.

'Painted Lady'
Hundreds of new faces arrive in Coober Pedy every year, many of them women.

Nikki Penissi has spent much of her life underground

They hope to find a "Painted Lady" - a rock covered with opal - or a "Virgin Rainbow", the name given to the town's most valuable stone, now locked up in an Adelaide bank vault.

"As soon as you see the colour, you hope to make millions tomorrow," said Nikki Penissi, one of Coober Pedy's female opal miners, who migrated to the town from Greece 35 years ago.

"After you lick a few stones you get the fever, opal fever. Make sure you don't lick the stones, because otherwise you're going to be here for 35 years."

Nikki has spent much of her life in Australia underground, either digging for opal or living in a dugout - a cave tunnelled into the side of a hill.

More than 50% of the town's population - currently 3,500 people - live in dugouts. The air inside is cool and still, away from the dust, flies and desert heat.

When European miners first discovered Coober Pedy's opal fields 90 years ago, some considered it bad luck for women to go down the mines.

But Anne Vanajek, a mother of three who has mined underground for 32 years, says hard work means she has always been treated with respect. "It wasn't easy in the early days - we'd go out to the field at night with two young children," she said.

"When they went to sleep I'd be sorting out explosives, starting the machinery and trying to sort out the washing and the ironing and all the other things that needed to be done."

"It is hard work physically, not recommended for someone who's frail. I'm lucky that I'm quite a robust person. I've always enjoyed the camaraderie I've had with other miners, they talk to me as an equal."

Today, some of the women of Coober Pedy are turning to other careers - in nursing, teaching or tourism - preferring a reliable income to gambling on opal.

But the women who are still miners say it is a stone they just cannot leave unturned.

"When I first came, I didn't understand what all the fuss was about," said Tania Burke, a German who met her husband in Coober Pedy when she visited as a tourist, and now mines with him everyday.

"They say diamonds are a girl's best friend, but opal is far more beautiful. I just adore it. It's a magnificent stone."