Has anyone come accross rocks like this?

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hAyyoUinAU

Rick
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I haven't done anything except wash it, inside is completely hollow. Has straight edges on outside, strange shape, like a cacoon.

1505464620_20170915_182752.jpg

1505464620_20170915_182820.jpg
 
Nice looking stone :Y: the hollow indicates petrified wood or a man made tool. Pretty sure it's petrified wood. Great find what ever it is, it's a keeper either way you look at it.
 
I found some stones that kinda look like that. I have like a bucket of them .... I have cut a few open and not all of them are hollow inside. I think they are volcanic?
I'll take some photos in a minute after dinner.
 
1505470581_20170915_201130small.jpg

1505470656_20170915_201153small.jpg


I found them at Wollongong.
I collected them thinking I would make vases or something out of them. I tried cutting a few open with a circular saw but they fractured.

Similar? but different. Yours looks like maybe it has organic looking fibres of something on the inside?
 
hAyyoUinAU's original pic looks like a fossilised sea-floor wormhole, which I think are found in lateritic rocks. I've seen them around Kalgoorlie and people were collecting them to sell at market stalls for a few dollars. There's probably a technical name, but it's 20 years ago now, and I can't remember what it is. :8
 
Sorry guys, was watching the footy game.

Great responses, thinkin Grubstake might be spot on. And yeah Dron yours do look a bit similar.

It is cool some of the unusual rocks we find. This one sure does look like something lived inside it at one stage.

Thanks for the responses too, I appreciate any help I get.
 
Although google doesn't help with "fossilised sea-floor wormhole"

Hmmm. Still interesting. Only because of the sharp flat edges and shape.
 
Firstly, I'm not a geologist.
I think you will find they are the same thing that we refer to in the boulder opal industry as "Ironstone concretions" .
Thought to have formed when iron accumulates through solution in sandstone. Classed as sedimentary, some of the ironstone and manganese forms i've seen (botryoidal shapes) can resemble something that has formed volcanically or has a "fused " look to it, like your picture .
This is what the "Yowah nuts" are.
I have found such concretions from my back yard near Brisbane to all the furtherest Queensland boulder opal fields.
Boulder opal is formed in them when rare geological sequence line up. the opal can be deposited during or after the formation of these "Boulders" (Larger ones) or "Nuts" smaller ones.
They usually can be found where there is plenty of iron banding in sandstone formations. Around Wivenhoe Dam where sandstone is eroded is one place I have found them, mostly with a small gravelly coating.
 
Keen Ken said:
Firstly, I'm not a geologist.
I think you will find they are the same thing that we refer to in the boulder opal industry as "Ironstone concretions" .
Thought to have formed when iron accumulates through solution in sandstone. Classed as sedimentary, some of the ironstone and manganese forms i've seen (botryoidal shapes) can resemble something that has formed volcanically or has a "fused " look to it, like your picture .
This is what the "Yowah nuts" are.
I have found such concretions from my back yard near Brisbane to all the furtherest Queensland boulder opal fields.
Boulder opal is formed in them when rare geological sequence line up. the opal can be deposited during or after the formation of these "Boulders" (Larger ones) or "Nuts" smaller ones.
They usually can be found where there is plenty of iron banding in sandstone formations. Around Wivenhoe Dam where sandstone is eroded is one place I have found them, mostly with a small gravelly coating.

Sounds on the money. A local too. Nice. Might run into each other one day
 

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