❓Your Mineral Identification Questions answered here

[Guessologist]

The geology at Mt William is of course completely different to Hanging Rock.
What is your source for the information that the colouring is caused by chromium and not nickel at Mt William?

I suppose you've got me there, I'm mostly inferring it from the abundance of chromian muscovite (the old 'selwynite') known further up the range. I doubt anyone has tested it. I guess the greenstones do have a relatively high nickel content despite the lack of decent Ni mineralisation so it could well be responsible. I honestly don't know too much about the geology of chrysoprase proper, but that's an interesting question - if both chromium and nickel are present when chalcedony is forming, does one contribute more to the colouration?

 

[user 4386]

The geology at Mt William is of course completely different to Hanging Rock.
What is your source for the information that the colouring is caused by chromium and not nickel at Mt William?

I suppose you've got me there, I'm mostly inferring it from the abundance of chromian muscovite (the old 'selwynite') known further up the range. I doubt anyone has tested it. I guess the greenstones do have a relatively high nickel content despite the lack of decent Ni mineralisation so it could well be responsible. I honestly don't know too much about the geology of chrysoprase proper, but that's an interesting question - if both chromium and nickel are present when chalcedony is forming, does one contribute more to the colouration?

That was the reason for my curiosity. The nickel present would be released during formation of the chalcedony (breakdown of olivine to silica and serpentine etc.), but muscovite (in fuchsite = chromium muscovite) does not break down readily at all but tends to stick around as flakes in the soil, as do crystals of chromite. The nickel content would be elevated in the Mt William rocks sufficient to give a pale colour to chalcedony (microquartz) but is far less than in the ultramafic (olivine-rocks) that tend to form good-quality chrysoprase. I tend to see that pattern in WA also - poor quality over weathering metabasalt, good quality over serpentinite (both rocks tend to be lumped as "greenstone" but the Mt William axe heads that I used to find along the creek between Mt William and Melbourne when I was young were metabasalt = "diabase", serpentinite is too soft for axes (but could of course be associated with metabasalt - I cannot remember details of Mt William, which is no longer accessible). Not trying to prove you wrong, just curious.

 

[Pat Hogen]

https://www.prospectingaustralia.co...ages/11777/1541591513_2018-11-07_22.50.06.jpg
https://www.prospectingaustralia.co...ages/11777/1541591513_2018-11-07_22.49.49.jpg
https://www.prospectingaustralia.co...ages/11777/1541591514_2018-11-07_22.49.19.jpg

Can anyone tell me what this may be? Or at least if it was manmade on natural.
It was found in the forest at hanging rock.

Looks like a botryoidal chalcedony - don't they find something similar to chrysophrase near Hanging Rock?

Big outcrop of Prase less that a km from Hanging Rock in a Southerly direction, not much further on from the Coprolite
poop: ). I recall a whisper that it is off the agenda for collecting, which would be a real bummer because it is really attractive rock.

 

[user 4386]

https://www.prospectingaustralia.co...ages/11777/1541591513_2018-11-07_22.50.06.jpg
https://www.prospectingaustralia.co...ages/11777/1541591513_2018-11-07_22.49.49.jpg
https://www.prospectingaustralia.co...ages/11777/1541591514_2018-11-07_22.49.19.jpg

Can anyone tell me what this may be? Or at least if it was manmade on natural.
It was found in the forest at hanging rock.

Looks like a botryoidal chalcedony - don't they find something similar to chrysophrase near Hanging Rock?

Big outcrop of Prase less that a km from Hanging Rock in a Southerly direction, not much further on from the Coprolite
poop: ). I recall a whisper that it is off the agenda for collecting, which would be a real bummer because it is really attractive rock.

Never sure what "Prase" means (in the eye of the beholder a bit). Chrysoprase is usually deep green chalcedony (bright, not dark but with good colour). Prase was originally applied to a rock - green quartzite. Although so loosely defined now that it is a bit meaningless, most people apply it to pale green quartz (strictly megaquartz, an example being green quartz crystals), not chalcedony. So do you mean green crystalline quartz in the case you mention?

 

[Joshlv]

Sorry im a complete novice but if it helps acid does nothing to it and i could scratch a gold coin with it.
Ill be taking it to my local lapidary club tomorrow to see if anyone can help

 

[Wally69]

Hi Josh, do you mean the Hanging Rock above Nundle or Victoria or one of the other Hanging Rocks scattered around our countryside?

 

[Pat Hogen]

Hanging Rock in Victoria? Is nothing sacred? Seriously? Is there any gold there?

According to Carpenter (1897) 77.75 kg of gold was won from the Lady of the Mountains (Ruzicka Hill gold mine, Hanging Rock) from 9tonne of stone.

And yes Wally, it is the leek-green crystalline variety of quartz known as Prase.

 

[user 4386]

Sorry im a complete novice but if it helps acid does nothing to it and i could scratch a gold coin with it.
Ill be taking it to my local lapidary club tomorrow to see if anyone can help

Then it is chalcedony - interesting (quite attractive). It is not calcite.

 

[user 4386]

Hi Josh, do you mean the Hanging Rock above Nundle or Victoria or one of the other Hanging Rocks scattered around our countryside?

I (and others) were assuming Victoria, but there is not much forest there.

 

[user 4386]

Hanging Rock in Victoria? Is nothing sacred? Seriously? Is there any gold there?

According to Carpenter (1897) 77.75 kg of gold was won from the Lady of the Mountains (Ruzicka Hill gold mine, Hanging Rock) from 9tonne of stone.

And yes Wally, it is the leek-green crystalline variety of quartz known as Prase.

Ruznicka was at the Hanging Rock near Nundle, not the one in Victoria (where there is not a trace of gold)

 

[Joshlv]

Sorry I should have said hanging rock above nundle nsw

 

[Guessologist]

Ha! I've learned something today, there's two Hanging Rocks. Chrysoprase it is then, no doubt.

 

[Pat Hogen]

Hanging Rock in Victoria? Is nothing sacred? Seriously? Is there any gold there?

According to Carpenter (1897) 77.75 kg of gold was won from the Lady of the Mountains (Ruzicka Hill gold mine, Hanging Rock) from 9tonne of stone.

And yes Wally, it is the leek-green crystalline variety of quartz known as Prase.

Ruznicka was at the Hanging Rock near Nundle, not the one in Victoria (where there is not a trace of gold)

Of course, and so is the Prase outcrop and the coprolite deposit.

Here is an interesting report on Ruzickas Reef, (Lady of the Mountain) -

Networks of vughy, crystalline quartz are present in some of the rocks on the dumps. Two parallel lines of reef may be present.

A block of gold weighing 30kg was won from a thin vein in flinty shales at this locality.

According to the Annual Report for 1882, Ruzickas Reef is synonymous with the Lady of the Mountain; according to Lloyd (1936) they are separate deposits. Records show that 11.2kg gold was found by Ruzickas in Dec, 1881.

 

[Joshlv]

Yeah there is also a hanging rock in the blue mountains, I've climbed it.

The closest thing i can find that resembles it is botryoidal chalcedony.
Correct me if im wrong but shouldn't chrysoprase be greenish. Photos may show colour but irl it is white

 

[user 4386]

Yeah there is also a hanging rock in the blue mountains, I've climbed it.

The closest thing i can find that resembles it is botryoidal chalcedony.
Correct me if im wrong but shouldn't chrysoprase be greenish. Photos may show colour but irl it is white

I agree
And there are a hell of a lot of Hanging Rocks, although those are the most famous in oz (one because of the Picnic at Hanging Rock movie in the 1970s

 

[Wishfull]

Yeah there is also a hanging rock in the blue mountains, I've climbed it.

The closest thing i can find that resembles it is botryoidal chalcedony.
Correct me if im wrong but shouldn't chrysoprase be greenish. Photos may show colour but irl it is white

I agree
And there are a hell of a lot of Hanging Rocks, although those are the most famous in oz (one because of the Picnic at Hanging Rock movie in the 1970s

Like that film
The house/girls school/ castle was built by a relative of mine. Edmund Bowman. He built it for his fiance that came out from England. She left him and he drowned in the Port Wakefield river. The place cost 30,000 in 1880.

 

[Shaza1]

Hey everyone
I found this in a creek bed, I have no clue, has anyone got an idea?
Thanks shaz

 

[Heatho]

Hi Shaz, looks like carnelian to me.

 

[liliane]

Hello shaza1, I found a rock like yours last year but I lost it lol , that is a good find keep it , carnelian hetho said so great, what a find, cheers

 

[hannahchikka]

Hi I'm new here.

This rock is black, very smooth, has a part thats grey on it (put it under a bright light and that part you can see through - no colour).
Its streak is white. Its texture is the same as a raw sapphire

Could it be black spinel or black sapphire?

Thanks