Rock & Gem


- By Jenni Clark and Leigh Twine

As a member of a few Australian Facebook fossicking (rockhoundi­ng) groups, I had been seeing photos of an amazing variety of cut and polished agates posted by people who had found them at Agate Creek. I had never been much interested in agates, but these photos really opened my eyes to the diversity and beauty of these round rocks. Now geography is not my strong suit – I leave that to Leigh – but when I realized that Agate Creek is actually up in our neck of the woods (North Queensland, Australia), arrangemen­ts were made to spend a few days there.

More than a century ago, prospector­s explored the area around Gilberton for gold deposits, as the region had shown a lot of promise for commercial gold mining ventures. It was discovered that an abundance of amygdule-derived agates had accumulate­d in one of the creeks that flowed into the Robertson River. These agates were believed to have weathered and eroded from basalts of Carbonifer­ous age, which were covered in sedimentar­y sandstone material when this region was an inland sea. The creek became known as Agate Creek and was first officially mentioned by W.E. Cameron in his GSQ report dated 1900. At that time, agate was thought to be beautiful but of little real value as mines in Germany and Brazil supplied the world market.

After World War II had affected Germany’s output, a couple of commercial mining companies began using machinery to recover sufficient quantities to make a viable operation. Unfortunat­ely, Agate Creek’s remoteness and lack of infrastruc­ture were against them. Lapidary and rockhoundi­ng became a more popular pastime for hobbyists. After some considerab­le conflict between miners and fossickers in the field, the Department of Minerals & Energy amended the regulation­s to prevent mining with equipment from being carried out at Agate Creek. Anybody could use hand-tools, but this, of course, led to the closure of the mines and the area being subsequent­ly declared a General Permission Area (GPA).

Although Agate Creek has been a popular fossicking spot and camping area for more than fifty years, it is a place that keeps on giving. The GPA is a roughly rectangula­r-shaped plain of some 45 square kilometres bordered by a rim of hills. Agate Creek itself runs the length of it, though it is dry for most of the year. The only approach to the GPA is a gravel road that heads south from the little gold-mining town of Forsayth. This road passes by the turn-off to the tourist attraction of Cobbold Gorge, so it is generally

well-maintained. However, corrugatio­ns, loose gravel, and dust mean that caution is required. In 2019, a gold mine adjoining the southern boundary was opened, with the ore transporte­d to Georgetown for processing.

The resultant constant heavy vehicle traffic has made the road a little more hair-raising for campers and caravans than in the old days.

There are two camping areas according to the map – the Agate Creek campground at the entrance to the GPA, and Safari Camp, situated at the far end of the GPA.

Although the gate’s sign proclaims it open, Safari camp is unattended and very run-down, apparently closed until further notice. The Agate Creek campground is well sign-posted and easy to find. It is a large flat area with enough trees to be pleasantly shady but leaving plenty of room so that campers aren’t in close proximity together.

This is just as well, as, during the winter months (April to September), Agate Creek is home to upwards of 50 people, many of whom stay for weeks or months at a time. They bring generators, rock-saws, and other lapidary equipment to process their finds on-site. One regular resident is reported to bring all the makings of a vegetable garden, which she plants, harvests, and completely removes upon leaving. There is ample potable bore water available and two well-appointed amenities blocks with a hot-water donkey for showers. A daily or weekly camping fee is charged by the owners of Old Robin Hood station, who own the GPA land and maintain the facilities.

It is expected that you leave the required cash in the honesty box at the camp entrance and take all your garbage home with you. Inland northern Queensland is not somewhere you want to camp in summer. It is very hot, very dry, and then unpredicta­bly flooding



occurs, making the roads impassable for days or weeks.

According to Wikipedia, agate is a ‘rock consisting primarily of cryptocrys­talline silica, chiefly chalcedony, alternatin­g with microgranu­lar quartz. It is characteri­zed by its fineness of grain and variety of color.’ It is a fairly common stone found in many locations worldwide, and each area tends to produce its own characteri­stic color range and banding effects. These depend on the circumstan­ces of how it was formed, what minerals were available to affect the hues, and what temperatur­es and time-frames it had to endure.

I’m told that an agate expert can often identify where a specimen was found simply by examining the colors, patterns, and internal structures. Agate has a hardness of 6.5 to 7 on the Mohs scale, making it suitable for most jewelry applicatio­ns as beads or cabochons. It can be carved into bowls and vessels and sculpted into decorative items.

Translucen­t, pale-colored agate is frequently sliced into thin slabs and dyed. The different components in the slab take up the dye to different degrees highlighti­ng intricate patterns. These slabs are then used in various applicatio­ns where the light shines through to reveal the banding effects and colors.

Agate Creek agate commonly displays a concentric banded pattern. However, other types such as moss agate, dendritic agate, seam and tube agates, banded onyx, and sardonyx can be found. While most nodules are solid

agate, others have an agate outer layer packed tightly with quartz crystals that grow inwards to fill the void.

Geodes are hollow agate nodules that are often lined with crystals of quartz, aragonite, or calcite. The attraction for agate-lovers is that every nodule has a different pattern and color structure – no two are identical.

Each named site at Agate Creek is known for its own particular color or design. Fossicking in the creek bed will present any variation as they have been collected and jumbled by floodwater­s.

Before making our trip, I researched Facebook requesting background knowledge from people who had actually been there. Several fellow fossickers offered helpful advice on their favorite digging areas based on what you are hoping to find – crystals, thunderegg­s, or even what color agates are predominan­tly found in each field.

We were also warned that the GPA is located on a working cattle station, and the herd had learned that easy pickin’s can be had by raiding camps while the occupants are off hunting rocks. Apparently, bread is a particular favorite. If you want to return to find your camp undisturbe­d, it is best to make anything tasty inaccessib­le to the bovine population.

To access the GPA, turn right out of the campground gate and follow the road southwards, taking the left fork at the Gilberton turn-off. The first field you come to is Black Soil on the left. Not really knowing what we were doing, we all disembarke­d and took a walk. Black Soil is literally that – a flat plain of dark, cracked, fine silt with broken pieces of agate and quartz everywhere you look. No digging is required, so grab a bucket and start collecting. Easy pickins’, indeed! These pretty little bits are great for your tumbler or cabbing, and they come in an astonishin­g array of colors and patterns. We were like kids in a lolly shop (candy shop) who couldn’t decide what to grab first!

It seems that this particular type of soil has a high moisture absorption ability, so when the yearly rains come, the flat plains flood with water and become quagmires. As the soil dries out, it cracks open in fissures, and this action brings the smaller stones to the surface.

I believe this is why Agate Creek has been producing agate for more than fifty years and will continue to do so for a long time to come.

As usual, if you are after the good stuff – the museumqual­ity specimens – you do need to dig. Should you come after a particular­ly heavy rain event, foraging in the creek beds will produce the odd, unexpected beauty. As a rule, the best stones require effort. Judging by some of the excavation­s we came across, it is evident that many fossickers expend a lot of energy and sweat. They probably return to the same site year after year, for months at a time. Agates and geodes can be found pretty much everywhere in this country – at the top of hills, in creeks, on the flats, in the sides of old riverbeds. There is a lot of untouched territory yet to be dug up.

Some diggings are a sandy loam, which yields easily to the pick and shovel. Others are virgin hillside or riverbank silt/clay soil requiring the removal of boulders to access the paydirt. Rough agates, unless broken, are quite unremarkab­le to the untrained eye.

Stones that we collected with great hope turned out to be ‘mud-rocks’ or ‘just-rocks.’ Stones that we nearly left behind have proven to be treasures once cut in half and the beauty within revealed. Agates can sometimes be distinguis­hed by the weight when held in hand. They are heavier for the size than you would expect due to the dense mineral compositio­n.

However, if the said specimen is actually an agate or chalcedony outer shell with a lining of crystals, it may be lighter than you expect and be tossed out with the rejects. It can take a while to get in the groove.

Crystal Hill is well worth a visit. It is located relatively centrally in the GPA, and a short walk up to the top gives you a spectacula­r 360-degree view of the whole plain. Some interestin­g permanent personal memorials have been constructe­d at the summit. I would love to know the stories behind them. As you can tell by the name, this is where geodes filled with white, clear, or smoky quartz, or occasional­ly amethyst crystals, are likely to be found. We spent a morning

there and found only small geodes, but we now have some lovely sparkly specimens in our collection.

There are other areas like ‘Bald Hill,’ ‘Mushroom Rock,’ and ‘Chimneys’ that are named after prominent landmarks or topography. ‘Pink Patch’ and ‘Green Patch’ are named for the predominan­t color of the stones found there. Some unique rock and mountain formations just beg to be photograph­ed for their sheer majesty and uniqueness.

As newbies to Agate Creek, we soon realized that we did not pack enough buckets, boxes, or rock transport receptacle­s. As rockhounds know, fossicking and collecting becomes addictive, and it is hard to leave a potential treasure behind. However, we had not accounted for the sheer weight of the material we wanted to take home.

Our campers’ floors were packed tight, and the back of our four-wheel drive was loaded full, leaving just enough room for the dog. Not only did we have lots of agate, but the banded jasper found in this area is also beautiful.

I acquired a couple of basketball-sized rocks that desperatel­y needed to live in my home rock garden. Unfortunat­ely, when I rolled one down the hill for Hubby to collect, it bounced at the last moment, striking him squarely on the shinbone. He has never allowed me to forget how I wounded him, and this story has become one of the family legends.

Apparently, there has also been gold found in the Agate Creek area. Hubby swung his mate’s detector for a couple of hours in a nearby creek and had only tinfoil and ring-pulls to show for it. Next time, he will be more scientific about where he prospects, and the return might be better.

It is impossible to spend time at Agate Creek and find nothing worth taking home, as there are beautiful rocks everywhere you look. In fact, the official rock pile of rejects at the camping area gate itself was easy pickins’ for us. We were not as fussy as the experience­d collectors who only take home the best. We left quite satisfied with our haul and look forward to using our newly-acquired lapidary equipment to show us what we really have!

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 ?? ALL IMAGES PROVIDED BY JENNI CLARK AND LEIGH TWINE ?? (Left) The easiest ways to remove dirt from the stone is to pressure clean with water. (Right) Even stones destined for the ‘leavearite’ (leave it right there) pile has potential to be further slabbed and cabochoned after a light polish in the tumbler.
ALL IMAGES PROVIDED BY JENNI CLARK AND LEIGH TWINE (Left) The easiest ways to remove dirt from the stone is to pressure clean with water. (Right) Even stones destined for the ‘leavearite’ (leave it right there) pile has potential to be further slabbed and cabochoned after a light polish in the tumbler.
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 ??  ?? A comprehens­ive map depicting the agate fields is found on the Department of Natural Resources and Mines, Queensland site.
A comprehens­ive map depicting the agate fields is found on the Department of Natural Resources and Mines, Queensland site.
 ??  ?? The creeks in the Agate Creek fossicking area are the best location to find stones of good quality.
The creeks in the Agate Creek fossicking area are the best location to find stones of good quality.
 ??  ?? Finding small agates in the host rock makes for easy pickins’ .
Finding small agates in the host rock makes for easy pickins’ .

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