Named in 2011, after Penny Williamson, curator of geology at the University of Wollongong, who was digging at the pocket when it was breached, the crystals are transparent and highly lustrous. Possessing daylight florescence, the deep green crystals have the added allure of turning an iridescent blue when placed in the sun.

Rogerley Mine, where Penny's Pocket is located, has other pockets with names not as pretty - such as The Dodgy Bugger, The Black Sheep and The Rat Hole - no prizes for guessing why.

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All, though, produce fluorite prized for its depth of colour and stunning crystal habits from cubic to octahedral.

As a child, Williamson would keep her eyes glued to the ground. An avid rock collector, she'd seek out the most interesting of specimens for her growing collection. This is a passion which has grown stronger with age. Her annual leave is mostly spent on excavations around the world, digging or sifting for the earth's treasures. Each year she attends mineral shows at Tucson or Denver in the United States, where mineral hunters gather to discuss their latest finds.

Williamson and associate professor Paul Carr are in charge of the University of Wollongong's rocks and minerals collection, now worth half a million dollars.

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In the foyer of the School of Earth and Environmental Sciences, the second half of the exhibit was opened in February and includes a small cluster of deep green, twinned fluorite, which Williamson pried from her namesake pocket last year.

"Fluorite would have to be my current favourite," she says. "With fluorite you get such a variety of shapes and colours. They are just exquisite. I was lucky enough to be invited to go and help excavate at the Rogerley Mine in 2011 and 2012 and we uncovered a pocket of fluorite in the limestone. We got some 'wow' material out. But in the last year the pocket has been become much larger, yielding some expensive samples, one of which weighs 150 kilograms."

Within the UOW collection is also a large green fluorite which hails from the William Wise Fluorite Mine in New Hampshire in the United States, donated by the mine's owner, Bob Borofsky. It's worth $10,000.

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Collectors are willing to pay big money for the finest pieces. Jewellers, too, are looking for the latest trends and finds.

Speaking from experience, actress Elizabeth Taylor once said: "Stones have a life of their own. There's something mystical about them. They have their own vitality". A testimony to the femme fatale's large jewellery collection.

There is something magical about many of the earth's sparkly, shiny treasures. Take the 400-kilogram amethyst which is a show-stopper at the UOW. People stare in wonder at the piece, prized for its purity and colour and which is worth a staggering $50,000.

"What I love is the beauty and diversity of minerals," says Williamson. "Some people get hooked on paintings. I'm hooked on minerals because it's nature's art. They are glorious and very valuable as collectors' items."

An example would be a tourmaline specimen, named the Candelabra, on display at the Smithsonian Institution in Washington DC and valued at more than $18 million.

Since metallurgist Professor Howard Worner donated his mineral collection to the UOW in 2000, Williamson and Carr have been building an international reputation in the hope of attracting more donations to the university.

"The Howard Worner Collection is what started the ball rolling," says Williamson. "He had a very fine eye for quality and he wanted the public to be able to enjoy his collection as much as he had."

Over 70 years, Worner acquired three collections. Many of his larger pieces were donated to museums when he moved from his family home in Melbourne to Wollongong in the mid-1980s. Although retired at the time, he continued his research through the UOW and it was his confidence in Williamson and Carr to take care of his collection that led to the donation. The result is that anyone can now walk into the foyer of the Science Building and view the 1000 pieces which range from rocks and minerals Worner excavated from sites near Broken Hill, to a display of meteorite specimens.

Worner, who was the most highly decorated civilian in Australia, died in 2006 at the age of 96. Some of his 18 awards and medals, which he received for his contributions to engineering, science and dental materials, are on display in the foyer.

Williamson has also been to Broken Hill searching for minerals, mainly for gypsum found in sandy soil at Woolcunda Station. Williamson has donated several pieces herself to the UOW collection, including a large sample of gypsum which she unearthed with Carr in 2004.

Her interest also extends to fossils and other oddities - including a cave bear paw dated at 50,000 years old, which was found in the Ural Mountains in Russia. The paw, which Williams purchased last year at the Denver Show, is three times the size of a modern brown bear.

The UOW's fossil cabinet also includes a dinosaur egg, a stromatolite, regarded as one of the oldest fossils in the world and a marine crinoids, discovered in Western Australia, worth $20,000. The university purchased the crinoids, which is similar in appearance to a sea lily, 25 years ago. The life form which existed 275 million years ago is now extinct.

"In the past 10 years we have been chasing other significant donations, which have resulted in the recent display," says Williamson.

"It's been a labour of love and a lot of work."

Williamson has been a board member for the past eight years of the Society of Mineral Museum Professionals and is the current vice-president.

"It's raised my profile," she says. "I also have to put together a program in Tucson each year under the banner of the UOW. As I'm usually the only Australian display, I focus on Australian rocks, minerals and fossils."

While there have been one-off donations to the university, in 2004, Matthew Webb, a Bendigo pharmacist, donated $200,000 worth of rocks and minerals.

His collection formed much of the recent exhibit.

"I specifically targeted Matthew as he had been donating a lot of material to the South Australian Museum.

"There was so much that they weren't displaying it. So I met with him in Tucson and told him what we were doing here at the university and he was impressed enough to make a big donation."

One of Webb's donations, a rubellite, which is a variety of tourmaline, is worth $20,000.

"I think it's fantastic that the people of the Illawarra have something like this collection on their doorstep," says Williamson.

She says Wollongong, from North Beach to Wombarra, is known for its petrified wood and agate to be found along the foreshore.

Other interesting finds include formations of ikaite along the foreshore rocks, indicating that Wollongong was positioned near Antarctica about 250 million years ago.

"Wollongong had icebergs floating around it," explains Williamson.

"We know that because some of the minerals found here only exist below 4 degrees Celsius.

"We can determine all that just from looking at local rocks."