Thunderegg Fossicking

 

 

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Cut open a 200 million year old mystery and fossick for treasures in the World’s largest thunderegg mine. Millions of years in the making, yet it only takes minutes to uncover a thunderegg from prehistoric volcanic lava. Thunderegg Fossicking is a great idea for your next school holiday activity on the Gold Coast as it is educational and fun and hands down one of the best Gold Coast hinterland attractions.

 

Entry fees include an informative explanation on thundereggs, how to find them, a mine safety talk, as well as the use of a pick and bucket to collect your treasures. Everyone gets to take home all the thundereggs that fit inside the rim of their buckets and will receive a souvenir miner’s permit as a memento. Additional eggs (above the rim) are charged at $3.00 per kilo.

 

The fun continues when we cut open your thundereggs with our custom made diamond edged saw blades to reveal the beauty of your very own mined treasures. Cutting is only $2.20 sq. Inch.

 

 

The mineral rich seam that runs through Mount Tamborine was discovered at Thunderbird Park in the 1930’s and opened to the Public in 1967. Today, the ground at 300m by 50m open-cut mine has an endless supply of beautiful thundereggs.

The name of 'thunderegg' originated in the United States, and refers to spherulite (spherical body generally occurring in glassy rocks, especially silica-rich rhyolites), a geological phenomenon greatly prized by collectors and amateur lapidaries.

 

The formation of thundereggs is much of a mystery, but it is thought that during volcanic upheavals in far-off times bubbles formed in silica-rich material such as rhyolite (an igneous, volcanic (extrusive) rock, of felsic (silicon-rich) composition). As cooling took place hot gases and steam expanded nodules in which they were trapped, and in these cavities some mineral structures joined together. Shrinkage of the material on cooling produced the star-shaped cavity which is characteristic of many thundereggs. Silica rich minerals entered the cavity, and solidified into chalcedony, jasper, quartz, agates and other beautiful minerals. Crystals were deposited on the walls, and the repetition of these processes produced the interesting patterns and colours which give thundereggs their universal appeal.

 

As the lava cooled crystallization of feldspar fibres occurred in a radical fashion around bubbles, and Cristobalite (a polymorph of quartz, meaning that it is composed of the same chemistry, SiO2, but has a different structure) filled the interstices in the radial network. Steam and gases which accumulated in the nodules interior caused expansion of the spherulite, and in some cases a large central cavity was formed by the internal gas pressure forcing the spherulite apart. Sometimes part of the whole of the cavity was subsequently filled with banded agate, chalcedony and quartz.

 

A beautiful display of these silica minerals and a wide variety of interesting structures make spherulites of special interest to gemologists and lapidaries. In Australia some well known collecting grounds for thundereggs are at Mount Hay (a smaller variety) and TAMBORINE MOUNTAIN IN QUEENSLAND. The most impressive and largest collection of thundereggs in the world is at Cedar Creek, Tamborine Mountain in Queensland. The thunderegg deposit here is on private property spread over 320 acres of lush rainforest. The thundereggs are found in all sizes, from a few grams in weight to over 600 kilograms, and they nearly all contain interesting fillings of agate and other varieties of quartz.

 

 

Monday to Sunday open from 9am
Last entry for the mine is 2.30pm with closing time being 4pm

* Closed on 25th December
* Open from 11am on ANZAC Day

 

 

Individuals 
$24 per adult 
$15 per child (3 - 12)

 

Groups
Price on application