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Published August 10th 2015
Fun with thundereggs and pewter figurines
Mount Hay Thundereggs and Pewter
Do you know what a thunderegg is? Would you like to fossick for your own, see gemstones being cut and polished and pewter figurines being made? Then Mount Hay Gemstone Tourist Park only 36kms west of Rockhampton on the Capricorn Highway is your one stop shop.
The home of Aradon fine pewter the park offers tours of the stone cutting and polishing area, and of the pewter works and also offers fossicking at the Mount Hay site. You will need at least one to two hours for all three activities. We have chosen both the tours and the fossicking but each can be done alone. We spend a half day but could easily have stayed much longer as once paid for there is no time limit to fossicking on the day.
Our tour guide first explains what rhyolite and thundereggs are and shows us examples of these and other gemstones in the gift shop. Stones at Mount Hay are volcanic. Spherultic rhyolite, a lava, is green, brown or red and is riddled with gas bubbles which are later filled with siliceous material. The polished slices of rhyolite are indeed beautiful. Some has been carved and polished as frogs, owls and skulls. The bubbled green stones look particularly good as frogs. Thundereggs are also lava which has formed around bubbles. These round stones are cut open to reveal patterns of quartz or agate within.
The park, which is also a caravan and camping park has shelter sheds and BBQ areas so why not take a BBQ or picnic lunch and make a day of it. You may get hooked on the fossicking, I know I did. There is a kiosk selling hot drinks, soft drinks and icecreams.
A gift shop sells polished thundereggs, pewter products and souvenirs, gemstones from other parts of Australia and some from overseas, jewellery and carvings. You are free to enjoy looking at the displays and it is worth spending some time.
The park is in an elevated position and we take time to admire the amazing views across the countryside. An added bonus at Mount Hay.
Mount Hay Gemstone Tourist park is 36 kilometres west of Rockhampton at 3665 Capricorn Highway, Wycarbah. It is signed at the roadside. Follow the dirt track about 500metres up the hill to the park. Don't worry it's not too steep and you don't need a 4WD. You can contact the park on 07 4934 7183, by email firstname.lastname@example.org or via their website. It is open 7 days a week, from 8.30am to 4.30pm. There is no fixed starting time and no limit on the time you can spend on the fossicking heap on the day. Costs at August 2015 are Fossicking Only: Adult $25, Child (5-17) $15, Under 5s $5, Family Rate (2 2 or more) - 10% off total price. Mini-tour (no fossicking): Adult $25. Child (5-17) $15, Under 5s $5, Family Rate (2 2 or more) – 10% off total price. Full Guided Tour: Adult $35, Child (5-17) $20.00, Under 5s $5 Family Rate (2 2 or more) - 10% off total price.
Gemstone Cutting and Polishing
After our introductory talk we move to the gem cutting and polishing area where we see different stone cutting machines, the saws of which do not have teeth but are really grinders.
Initial polishing of the cut stone is done in a shallow rotating, vibrating drum in which a fine abrasive is placed on a steel surface in water. Stones are weighted down with lead stuck on with soluble glue. Our guide lifts the drum's cover. The weighted stones are mesmerizing, almost hypnotic as they slowly wiggle their way around the drum. This 'rough' polishing takes a number of days and removes the fine grooves from the cutting of the stones. In a corner on a bench, boxes of lead weights of varying sizes are stacked ready for use.
Slices of rock and stone weighted with lead being rough polished in a rotating vibrating drum.
The final polishing is done in a vibralap, a similar machine to the first. This takes two days but this time the abrasive is a fine white powder, usually aluminium oxide, and a plastic sheet covers the steel surface of the drum. In all it takes seven days to polish the stones. Our guide lifts one of the stones to show its progress.
Tourists who do not wish to spend the money or time can use varnish or nail polish to highlight the patterns in the stones.
Next we are treated to a tour of the pewter operations. In the main, small souvenirs are produced; Australian animal ornaments, letter openers and coasters. The frilled neck lizard is my favourite. The business also fills orders for industry, such as plaques and awards.
First a design is sculpted in wax which is used to make a bronze casting. The bronze casting is used to make a mould in rubber. Each mould can cater for up to six figures depending on size. Our guide passes us some open moulds. I have one for koala figurines. Shelves under the benches are stacked high with the round moulds which are about the size of old film reels. Pewter ingots are melted down and when molten is poured into the moulds. The moulds are spun to force the pewter through and eliminate air bubbles.
Six pewter didgeridoo players straight out of the mould
After the pewter is removed from the mould, the figurines sit at the end of spiral arms. The spiral arms are then cut from the items. The next process is finishing. The tiny ridges made where the two sides of the mould join are removed with a small drill, scouring pads or a fine grinder. Polishing is done in a rotating drum with water and ceramic beads which looks like a large Mixmaster. Some of the figurines are coloured for effect.
Polishing pewter letter openers in a rotating drum of ceramic beads and water.
Our guide cheerfully answers our questions. This close up view of a thriving and interesting family business is well worth the visit.
Fossicking for Thundereggs
After the tour we are keen to start fossicking for our own thundereggs. We are given a rock hammer, a bucket of water, a scrubbing brush and a bag for our finds and taken to a pile of material excavated from the mine site at Mount Hay. Our guide reaches down and immediately picks up a small thunderegg, highlighting its smooth ball like shape.
Finding the thundereggs in the loose dirt pile is not hard work and so can be enjoyed by adults and children alike, just be sure to wear closed shoes. The rock hammer is used to chip away the surrounding hard clay. The scrubbing brush and water bucket are used to further clean our finds. We find many small thundereggs some of which are already broken with the crystals inside clear to see. We also find spherultic rhyolite and black volcanic glass.
Thundereggs - created by gasses trapped in Rhyolite lava.
Our finds are ours to keep so we collect small whole and broken thundereggs as souvenirs for our grandchildren before continuing our search for larger specimens. The fee for fossicking includes cutting of one or two thundereggs depending on the size. Others can be cut for a fee and polishing can also be arranged for a fee.
A thunderegg sliced - gas pockets are filled with quartz, amethyst, agate or jasper
Our finds are on the small side and the staff happily cut not only a couple of our thundereggs but some of the rhyolite we have found. Each is different inside and each has its own beauty. We are pleased with our bounty.
Where:3665 Capricorn Highway, Wycarbah, QLD. (36kms west of Rockhampton on the Capricorn Highway)
Cost:(At August 2015) Fossicking Only: Adult $25, Child (5-17) $15, Under 5s $5, Family Rate (2 2 or more) - 10% off total price. Mini-tour (no fossicking): Adult $25. Child (5-17) $15, Under 5s $5, Family Rate (2 2 or more) – 10% off total price. Full Gu