Chalcedonized petrifed wood from volcanic area

Here are some specimens of petrified wood I picked up from gravel banks of a river that flows through an area of extinct volcanoes. It might be that this kind of petrified wood is rare in Australia. If it is not directly related to the volcanoes in the area then it seems a bit of a coincidence and I have never found petrified wood so abundantly as I have here. I would think that fact that it has carnelian/agate growing over it/through it suggests thermal activity was a factor in the petrification process. Elsewhere in Australia, this may not have been the case.

Two bits with orange chalcedony on the outside and the cabbed pieces has blue agate with tiny quartz crystals in the middle.



As you can see, this piece is a petrified branch stub broken off a main trunk. There are very clear growth rings across the broken off section but I thought that it can be very clearly seen what this is without that.



Here is some of the material that typically accompanies the petrified wood, though most pieces are less interesting. It's a real shame that only the tiniest fraction of it has that vivid orange-red right through, usually it's just a thin skin with colourless material inside. Some rather unusual botryoidal chalcedonic growths as well, like a bunch of fish eggs. I have a few others that look like short columns.



If you're in/heading to the Rockhampton area in Central QLD and you want to grab some, just let me know and I will give directions. But you'd better get in quick - the Rookwood weir is on the cards and once it's built, these gravel banks will be drowned 8.(

Nice specimens lefty, I've never seen anything like the first 2 pics.

Cheers Heatho. I had a couple more of those but I sawed them up to confirm that an orange and white chalcedony went right through them - which it did, but there was also a lot of hollow spaces that made those bits unsuitable for cabbing.

Biggest bit of pet wood I've found there is also very obvious as to what it was - no chalcedony on it though. See if I can find a pic.

This is it - a petrified section of a tree trunk, not a cross-section but you can see the big knot that would have been a branch at some stage.

The carnelean looks cool on it, some awesome bits in there left. Sick haha

AtomRat said:

The carnelean looks cool on it, some awesome bits in there left. Sick haha

Click to expand...

I'm always looking out for an entire stump or trunk section covered/filled with chalcedony - if I can find one of those before they drown the area I'll be happy.

Still not happy that they intend to drown a good fossicking area. But they insist the city is going to need the additional water supply.

Some beautiful pieces there Lefty.
Over the last year i have been on the hunt for petrified wood, jasper, chalcedony and agate form a few places local to me. Whilst i have not found anything as nice as your collection i have found a few goodies that keep me going back. Will try and post a few photos later when photobucket is up.

Oh crap..not another reseviour / catchment deal...
Get in to speak to whoever you can and get the local gem club or something in there to get something at least. Soo much has been lost here never to be seen again. From gold to sapphire.. all deep under silt and water now. It sucks

Get some sort of deal / contract with someone mate. It should be illegal to remove a whole mineral deposit. We will be paying for air soon.. .

Cheers shivan, be interested to see your bits.

Edit: Of wood :lol:

Some more random bits from the same site. Not all are pet wood. There are quite a lot of chalcedony bits not shown, think I've put them away elsewhere.



This piece resembles fossilized coral.



Probably 40-50kg of material here - but that's been collected being very picky and originally ignoring the wood and jaspers and just looking for the chalcedony. You could probably pick up this much in half a day if you weren't picky.

Fossil wood CAN also be silicified by hot water related to hot springs and volcanoes (eg Nevada), which is where the original idea came from, but this origin is rather rare in Australia, Likewise opal can form this way and I know of such examples recorded in New England NSW (eg precious opal in cavities in vesicular lava) and in veins at Beechworth and Collgardie. But in Australia it would probably not be the origin 0.1% of opal or fossil wood

Click to expand...

As I've thought about it more, I think I have to respectfully question the accuracy of this statistic.

The volcanic ground in eastern Australia covers probably hundreds of thousands of square kms - I live nearly halfway up QLD and when I drive north the 1200 km to visit the in-laws, the countryside is igneous for the entire drive and this also extends a long way the other direction into NSW, with outliers to the west everywhere up and down that length. I tend to think that wood silicified by processes related to volcanics may make up significantly more than 0.1% of Australia's total.

In addition to what I have shown, there was an opalised wood deposit at Springsure in central QLD, about an hour and a halfs drive south of the Anakie gemfields. The area is unmistakably volcanic with volcano cores being the dominant landscape feature. The deposit is now closed after some ***** took an excavator and dump truck in without the property owners permission and ripped out several tonnes of material But I'm pretty certain this fossilized wood is volcanically-derived. I was too late to get into the site (several of my club members have been) but a short distance up the road is a deposit of faceting quality plagioclase feldspar (labradorite) which I have visited a number of times. Everything here is definitely volcanic, the feldspar crystals in the black basaltic soil....



.....this chunk of vesicular basalt lava and I will say almost certainly the wood as well.



Some distance the other direction from my home near the town of Monto, a kind of chalcedonised wood is known to local fossickers and my grandfather went and dug some. It's gone now - much of his collection went after he died - but dad says it resembled agatized tree roots, some bits had recognisable growth rings. Again, this area is volcanic.

I've never been to Chinchilla in SE QLD but quite a bit of colourful pet wood came from there and I believe the countryside is again volcanic.

In summary, I tend to think that the reason I assumed petrified wood to be usually of volcanic origin is because is that is likely to be the case for thousands of kms around where I live. Accordingly, I think volcanically-derived silicified wood likely makes up a not-insignificant portion of all the material in Australia, perhaps even a fifth or a quarter.

Does anyone have any thoughts on the matter?

Nice stuff lefty you always have the nicest gems l hope to have a collection like this to one day I always look out for your post thanks for showing all off us your gems and thanks for taking the time to posting photos I tell my family you are the rock god of the forum good luck lefty hope to see more of your finds thanks LGH :lol:

Yay, I've bee reinstated to Rock God status! :lol: Thanks LGH!

Just keep at it, a collection is something that builds up over time - a years and years. I do have some nice rocks but my dad is 70 years old and has been collecting since he was about 21 and his collection blows mine away.

School holidays not too far away, you should be able to do a bit of rock hounding if it's not to hot.

You do have some beautiful pieces Lefty.

My pieces do not come close to yours, but i enjoy finding them.








A lot of the wood down my way is back when cut open, but there are the exceptions.








I have found a little chalcedony and agate, but nothing like the bits you have showed, though there seems to be some obsidian as well.













A little potch seam from the same area.


All the bits that dont make it in the collection or need a little weathering go in the garden.

You do have some nice pieces there Shivan - much of the wood I find is black when sawn open as well. There are some colourful bits and some nice bits of banded agate as well.

Do you cab? Some of those pieces would make nice cabs.

Cheers

Cheers lefty.
With the pieces you cut that are black, if they were nice pieces, you can put them out in the sun and rain and weather the colour back into them. It takes a while and thinner pieces get colour back quicker than thick bits. But this has allowed me to recover a few nice specimens.

Yes i love to cab Lefty, i have done a few cabs from this material, but am saving the bulk of it for later. Once i am good enough i would like to try my hand at selling jewelry made from local rocks and local gold. Not sure if it will ever happen but thats the goal.

Once i am good enough i would like to try my hand at selling jewelry made from local rocks and local gold.

That idea really does it for me as well

I love being the first person to see something tumble from it's millions of years old hiding place in the earth and then to work it to a finished gem, be it cabbed or faceted. To make jewellery from local materials - especially found by myself - is something I really want to start doing.

I've only done a very small amount of setting but I have a mate who is a manufacturing jeweller who now only requires occasional use of his burnout kiln and casting centrifuge, so he's going to bring them out and put them in my workshop - be no stopping me then!

Yes there is something a bit special about watching a piece of stone get transformed during cutting and polishing, makes it even more so when you have found it yourself.

I have not done any setting yet, but would like to start soon. Will start with a few blanks and see if i can cut the stones to suit, then when i can afford the gear i will move on to the silver working then gold. Wish i had a mate who was a jeweller, that is very handy Lefty.
I am hoping to make a few people presents for christmas this year so will see how i go before i get ahead of myself.

Very nice shivan thanks for showing love looking at every one and this helps me know more about them and what to look ? for thanks again and keep on posting and good luck LGH :lol: