Learning Center What is a mineral?The most common minerals on earth Information for Educators Mindat Articles The Elements The Rock H. Currier Digital Library Geologic Time

Minerals by Properties Minerals by Chemistry Advanced Locality Search Random Mineral Random Locality Search by minID Localities Near Me Search Articles Search Glossary More Search Options

The Mindat Manual Add a New Photo Rate Photos Locality Edit Report Coordinate Completion Report Add Glossary Item

Mining Companies Statistics Users Mineral Museums Clubs & Organizations Mineral Shows & Events The Mindat Directory Device Settings The Mineral Quiz

Photo Search Photo Galleries Search by Color New Photos Today New Photos Yesterday Members' Photo Galleries Past Photo of the Day Gallery Photography

Discussions

💬 Home 🔎 Search 📅 Latest

╳Discussions

💬 Home 🔎 Search 📅 Latest

Groups

Recent Images in Discussions

27th Sep 2019 17:39 UTCErik Vercammen Expert

We need more information like hardness, streak, dimensions, if possible density..but a wild guess: pyrite, slightly oxidized causing the reddish tinge.

27th Sep 2019 18:12 UTCPeter Nancarrow 🌟 Expert

I would say that it looks rather too light in colour for chalcocite, but given that your specimen appears to be a fairly large massive piece, if it is fairly pure, it should be fairly easy to determine its cleavage, hardness and SG.

Those properties would certainly allow pyrite and chalcocite to be distinguished from one another.

You could also consider another possibility, which is native bismuth, quite large pieces of which were found at that locality back in the 19th Century.

See:

https://www.mindat.org/gallery.php?loc=1262&min=684

Pete N.

27th Sep 2019 18:22 UTCTimothy gee clarke

Hi there's a silver streak on porcelain, and the specific gravity is 9.6,if I've done it right

27th Sep 2019 19:53 UTCKnut Eldjarn 🌟 Manager

Native bismuth seems likely. Nice, rich specimen!

Knut

27th Sep 2019 20:01 UTCTimothy gee clarke

I'm hoping it is,I've got 8 more pieces

28th Sep 2019 01:14 UTCThomas Lühr Expert

A needle tip will easily leave an imprint in native bismuth if you slightly push (not scratch)

28th Sep 2019 01:36 UTCPaul Brandes 🌟 Manager

If you've done your SG and streak correctly Tim, Knut's suggestion of native bismuth seems plausible.

28th Sep 2019 10:52 UTCTimothy gee clarke

Thanks for the help it’s much appreciated,I’ve spent 35 years picking up rocks ,I’m only now getting round to naming them

Tim

28th Sep 2019 11:44 UTCTimothy gee clarke

Looks like I might have potentialy quite a few peices thanks again

Tim

28th Sep 2019 18:16 UTCTimothy gee clarke

Hi is this one the same it has specific gravity of 9.8 it leaves a silver streak,but has no reddish tinge it's from the same place

28th Sep 2019 21:13 UTCKevin Conroy Manager

This one looks like it has chalcopyrite present.

I'm not familiar with this locality so I wanted to wait and see what the local experts thought about the first specimen. The photo is a little fuzzy, but it looks like there are a few light gray smooth bits included in the piece so I thought this may be slag. I REALLY hope it isn't! Is there a chance that a clear shot or two of the bits be posted so the slag possibility can be eliminated?

28th Sep 2019 21:38 UTCTimothy gee clarke

Hi I hope this picture is bit clearer

Tim

28th Sep 2019 22:10 UTCKevin Conroy Manager

Hi Tim,

The last photo looks good, but I meant the original specimen that you showed us. Sorry about the confusion.

28th Sep 2019 22:19 UTCTimothy gee clarke

That's the one hope it is clearer

Tim

29th Sep 2019 00:19 UTCKevin Conroy Manager

Thank you. I'm not seeing anything that looks like slag so that's a great relief.

29th Sep 2019 00:24 UTCThomas Lühr Expert

With the new photos it look not like bismuth to me anymore but rather like some kind of a smelter product, like ferromanganese, ferrochrome etc.

Do the test with the needle, that I suggested above, it is distinctive.

29th Sep 2019 01:20 UTCTimothy gee clarke

Hi I have tried the pin test it does leave a indentation it's very easy to scratch as well ,I'll be happy what ever it is

29th Sep 2019 15:36 UTCPaul De Bondt Manager

Bismuth melts in the fire of a candle.

Looks like arsenopyrite to me.

29th Sep 2019 16:26 UTCTimothy gee clarke

I’ve tried melting them,apart from burning my finger they did not melt

29th Sep 2019 17:16 UTCPaul De Bondt Manager

So absolutely no bismuth.

Was there a garlic smell when hot ?

Arsonopyrite.

29th Sep 2019 17:20 UTCTimothy gee clarke

Yes there was ,used a blow torch on them definitely no bismuth ,thanks for the tip

Tim

29th Sep 2019 18:51 UTCThomas Lühr Expert

Meight be lollingite though, which is heavier than arsenopyrite and would be fit the hight density.

Hold a crumble with tweezers and heat it *carefully*. Arsenopyrite will give a sulfur smell first and then at higher temperature the garlic smell of arsenic.

The sulfur smell is missing at lollingite.

DO NOT INHALE THE WHITE SMOKE!

I wonder about the behavor to the needle and the silver streak, that would rule out arsenopytite and lollingite as well.

Tim, can you see at one of your specimens some adhering hostrock / matrix? If not then some kind of a smelter product is likely. Do you know where and under which circumstands it was found?

30th Sep 2019 13:06 UTCTimothy gee clarke

Here's the back of the rock, I didn't smell sulfur and it still leaves a silver streak,I found this one at the consols mine site when I was a child,it was our local place to play,I've taken a couple of up close shots hope they help

Tim

30th Sep 2019 13:12 UTCTimothy gee clarke

another pic

30th Sep 2019 13:13 UTCTimothy gee clarke

another one

Mindat.org is an outreach project of the Hudson Institute of Mineralogy, a 501(c)(3) not-for-profit organization.
Copyright © mindat.org and the Hudson Institute of Mineralogy 1993-2024, except where stated. Most political location boundaries are © OpenStreetMap contributors. Mindat.org relies on the contributions of thousands of members and supporters. Founded in 2000 by Jolyon Ralph.
Privacy Policy - Terms & Conditions - Contact Us / DMCA issues - Report a bug/vulnerability Current server date and time: April 27, 2024 03:35:03

Go to top of page