We use cookies to show content based on your preferences. If you continue to browse you accept their use and installation. More information. >

FMF - Friends of Minerals Forum, discussion and message board
The place to share your mineralogical experiences


Spanish message board






Newest topics and users posts
29 Sep-10:49:34 Re: collection of volkmar stingl (Volkmar Stingl)
29 Sep-03:18:48 Re: baryte collection of niels brouwer (Tobi)
29 Sep-03:09:19 Re: favourite fluorites? (Tobi)
29 Sep-02:28:31 Re: favourite fluorites? (James Catmur)
28 Sep-18:43:27 Re: favourite fluorites? (Niels Brouwer)
28 Sep-18:06:43 Re: a mineralogical trip through italy by sante celiberti (Sante Celiberti)
28 Sep-18:01:52 Re: baryte collection of niels brouwer (Niels Brouwer)
28 Sep-14:18:07 Popular minerals - prehnite from la combe de la selle, france (Jordi Fabre)
28 Sep-10:10:33 Re: collection of volkmar stingl (Volkmar Stingl)
28 Sep-09:48:11 Re: collection of volkmar stingl (Volkmar Stingl)
27 Sep-18:10:14 Re: a mineralogical trip through italy by sante celiberti (Sante Celiberti)
27 Sep-13:04:15 Re: collection of tobi (Tobi)
27 Sep-11:42:49 Re: what's up with minfind? (Lluis)
27 Sep-11:06:21 Re: collection of joseph d'oliveira (Joseph Doliveira)
27 Sep-10:57:45 Re: what's up with minfind? (Jesse Fisher)
27 Sep-10:49:37 Re: what's up with minfind? (Bob Kerr)
27 Sep-10:22:48 Re: collection of firmo espinar (Firmo Espinar)
27 Sep-10:07:48 Re: what's up with minfind? (Peter Lemkin)
27 Sep-09:53:11 Re: what's up with minfind? (Lluis)
27 Sep-09:48:34 Re: collection of michael shaw (Michael Shaw)
27 Sep-09:38:34 Re: collection of tobi (Michael Shaw)
27 Sep-08:58:44 Re: collection of tobi (Tobi)
27 Sep-06:40:18 Re: what's up with minfind? (James Catmur)
27 Sep-03:29:08 Re: collection of tobi (Dany Mabillard)
27 Sep-02:38:15 Re: what's up with minfind? (Gregc12345)

For lists of newest topics and postings click here


RSS RSS

View unanswered posts

Why and how to register

Index Index
 FAQFAQ RegisterRegister  Log inLog in
 {Forgotten your password?}Forgotten your password?  

Like
72531


The time now is Sep 29, 2020 12:04

Search for a textSearch for a text   

A general guide for using the Forum with some rules and tips
Does anyone know what this may be?!
  
  Index -> What is it? - Where is it from?
Like
1


View previous topic :: View next topic  
Author Message

Aetherian




Joined: 20 Aug 2020
Posts: 1
Location: Washington

View user's profile

Send private message

PostPosted: Aug 21, 2020 07:24    Post subject: Does anyone know what this may be?!  

I found this buried pretty tightly shining at bottom of river here in Washington State


20200820_163414.jpg
 Mineral: Unsure
 Dimensions: About 10 inches across and 8 inches tall. Weighs about 60 lbs
 Description:
 Viewed:  541 Time(s)

20200820_163414.jpg


Back to top
Reply to topic Reply with quote
Like
   

James Catmur
Site Admin



Joined: 14 Sep 2006
Posts: 745
Location: Cambridge


Access to the FMF Gallery title=

View user's profile

Send private message

PostPosted: Aug 21, 2020 07:34    Post subject: Re: Does anyone know what this may be?!  

It is a large rock containing quartz
Back to top
Reply to topic Reply with quote
Like
   

Pete Richards
Site Admin



Joined: 29 Dec 2008
Posts: 698
Location: Northeast Ohio


Access to the FMF Gallery title=

View user's profile

Send private message

PostPosted: Aug 21, 2020 09:14    Post subject: Re: Does anyone know what this may be?!  

I think this might be a pyrite nodule, composed largely of pyrite (fool's gold), iron sulfide, which is quite dense as mineral go.

So I'm guessing this is rather heavy for a rock of its size. If you had some way to estimate its volume, then we could calculate an average specific gravity for the entire stone.

One way to do this: Fill a bucket to the top with water. Immerse the rock in the water. An amount of water equal to its volume will spill out (do this outside...) Remove the rock. Using a measuring cup, fill the bucket to the top again, keeping track of how much water it takes to fill it. That's the volume of the rock. The specific gravity is the weight divided by the volume. Any value greater than about 3.0 would be above average for typical rocks and minerals. Pure pyrite would be about 5.

_________________
Collecting and studying crystals with interesting habits, twinning, and epitaxy
Back to top
Reply to topic Reply with quote
Like
1
   

Pete Modreski
Site Admin



Joined: 30 Jul 2007
Posts: 685
Location: Denver, Colorado


Access to the FMF Gallery title=

View user's profile

Send private message

PostPosted: Aug 21, 2020 11:05    Post subject: Re: Does anyone know what this may be?!  

I'll agree, that this is most likely pyrite, Aetherian. Likely mixed with quartz (if there's obvious white mineral material with it). If the whole rock is pyrite, it should feel REALLY heavy.

If it were gold (VERY unlikely), you'd be able to scratch the golden-metallic material easily, with the point of a knife or a nail. Pyrite is hard enough, it won't scratch.

Another test, if you break off a crumb of it, hit is with a hammer on a hard surface and pyrite will shatter to a powder, which will look more of a greenish-metallic color. And you likely will smell a whiff of sulfur, if you powder it that way.
Back to top
Reply to topic Reply with quote
Like
   
Display posts from previous:   
   Index -> What is it? - Where is it from?   All times are GMT - 5 Hours
Page 1 of 1
    

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum


All pictures, text, design © Forum FMF 2006-2020


Powered by FMF