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A guy was telling me that Pipeclay is super heated Quartz that has melted down and dissolved into Pipeclay. I'd never given it much thought? So I'd like to know if he's right?
Wiley.
Wiley.
Swinging & digging said:Pipeclay is decomposed slate. Its NOT QUARTZ, whoever told you that is simply WRONG.
UnderEmployedGeo said:
Moneybox said:UnderEmployedGeo said:
Excellent illustrations UnderEmployedGeo and I love the colours but where is the gold? layful:
12 actually - "on the one hand...but on the other...."UnderEmployedGeo said:Moneybox said:UnderEmployedGeo said:
Excellent illustrations UnderEmployedGeo and I love the colours but where is the gold? layful:
Don't ask me!
There's a saying about geologists - get 6 of them in a room together and you'll get 7 opinions.
Moneybox said:UnderEmployedGeo said:
Excellent illustrations UnderEmployedGeo and I love the colours but where is the gold? layful:
wiley coyote said:The pipeclay where I detect is a creamy/white colour, feels slippery to touch, like talcum powder. Is it correct that the old timers dug through the wash dirt to the pipe clay, then tunnelled along in it as It was easier to work, took It up to the surface, then dropped the wash dirt down into the tunnel, then took that up to the surface to process. I've heard differing versions of how they worked It, but this seems the most logical way to me. Any thoughts on this? wiley.
20xwater said:
UnderEmployedGeo said:Add this to the list of confusing historic terms that actually make less sense to the geologists among us (guilty) than to normal, sensible folk with better things to worry about. Whenever I see references to "pipeclay" my mind just shuts down and stops working (if it was working to begin with that is).
Thank you once again to Goldierocks for some actual geology.
One other one is references in older materials to "pitted shale" or pitted whatever - THAT I understand - the pits would be where there used to be little sulphide crystals in the original fresh rock. Slates are pretty resistant to weathering, but sulphides are not. First they oxidise, then they get washed out completely, leaving little "pits". Sulphides are pretty common around gold deposits like you see in Vic (and parts of WA).
A similar thing happens in quartz-carbonite veins (of the sort that often carry gold in gold fields) - if there were enough sulphides in the fresh rock, the preferential weathering of the sulphides can lead to a sort of honeycomb texture, that is better described in geology as "boxwork texture" - lots of little roughly cubic holes that once were full of sulphide crystals, now just full of iron staining. Boxwork textures are a good sign, just as laminated iron-quartz can also be.
Back to clay minerals - in the outer western suburbs of Melbourne, where the Newer Volcanics (basalt) have weathered to clay, there is a particular smectitic clay type known as Montmorillonite - and it is incredible at absorbing water, expanding hugely when wet. People have literally broken their house slabs in half by accidentally leaving a garden sprinkler on...
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