❓Your Mineral Identification Questions answered here

[Rabetech]

Any ideas? This triggered a large non-ferrous signal on the gold monster, found in an area close to the iron blow, is reasonably heavy for its size, very hard surface, and no conductivity.

Thanks.

 

[Hawkear]

Generally in dealing with a mystery “hot rock”, break it and if there is no gold seen and each large piece of the rock continues to give off a signal or it disappears then it can usually be assumed it is just a hot rock.
In addition you are able to see what the rock is truly made of as the outer weathered surface can be vastly different to the freshly exposed inner surface.
If a quartzy matrix is exposed maybe crush it further to check for fine gold In a pan.

 

[Dave79]

Native copper is common round there.

 

[Rabetech]

Native copper is common round there.

Would think so, not exactly sure what it looks like though I had the impression it may be, but no conductivity even at close probe prox. Thanks for response.

 

[Rabetech]

Generally in dealing with a mystery “hot rock”, break it and if there is no gold seen and each large piece of the rock continues to give off a signal or it disappears then it can usually be assumed it is just a hot rock.
In addition you are able to see what the rock is truly made of as the outer weathered surface can be vastly different to the freshly exposed inner surface.
If a quartzy matrix is exposed maybe crush it further to check for fine gold In a pan.

Totally, I do intend to crack this nut, but haven't yet, does certainly feel heavier than it should be, I will post pix of internal when I get to 'opening' it thanks for response.

 

[mbasko]

I feel the very even and fine grained crystalline appearance seems more typical of a basaltic texture rather than a sandstone. Basalt is made of micro mineral crystals whereas sandstone is generally composed of rounded grains.
Its colour yellowish/brown is also typical of a weathered basalt as shown in the attached. Importantly these weathered basalts can still retain much of the even grained crystalline structure of the original basalt as many other unaltered crystals of different minerals remain interlocked. The weathering of a sandstone will most often loosen the grains as it is the cementing iron rich material that is altered.
There are many basaltic flows in the Daylesford goldfield areas still capping the basement slates and sandstones.
The Daylesford area is also renowned for its mineral springs many of which are high in sulphur. The creeks around the area drain this mineral water and on exposure to air the sulphur oxidises to a weak sulphuric acid. Many attest to the health qualities of these springs but they are just awful to drink. Tried them many times yuk!
Over time but in relatively short geologic time, any weathered fine grained basalt rocks falling from the high basalt cappings into Daylesfords deeply cut watercourses containing this very weakly acidic mix of mineral and run off waters could have its available iron content leached from the surface inwards. This could in turn produce the rinded or peel like structure shown in the sample with the pale iron leached zone on the outside of the rock.
I am not so sure about the timing of the internal weathering and outer leaching events ie whether they were simultaneous events or whether the weathering occurred first.
Perhaps a search might reveal freshly broken weathered but non surface leached samples in the area which might indicate the former.
My two bob opinion

All the weathered/broken down bits of basalt I've encountered are still dark grey to black internally. A lot do have a light colour thru to rust red brown exterior.
Examples:
Outside showing light colour to rusty red.

Internal


Basalts typically retain the dark grey/black due to the manganese & pyroxene, weathering or "rusting" from the outside.
The sample also appears not to be fine grained enough for basalt & high in silica content (quartz grains). Basalt is low in silica.
Hard to tell from a photo on phone & not a lot of info.

If it's grainy & friable (crumbly) when broken I'm sticking with my initial amatuer guess

Either way it's definitely iron mineral content giving it the red colour.

 

[Amyyb7579]

So I found this rock alongside a running creek in NSW- Upper Allyn/Eccleston/LadysWell area and was hoping to get some thoughts and opinions as to what it could be.

Happy to answer any questions or provide more photos to help with the I.D

Thanks
Amy

 

[mitchy93]

i think quartz with some iron or dirt in it? i found on the side of the road in cootamundra, nsw last weekend. got bored yesterday and tried to polish it up a bit with some high grit sandpaper (tumbler arriving this sunday)