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

FMF English Forum is moderated by John S. White and Peter Megaw
 

Spanish message board






Newest topics and users posts
22 Sep-14:45:44 The mizunaka collection - fluorite (Am Mizunaka)
22 Sep-10:22:43 Re: someone told me this is what happens to mud at the bottom of a lake (Bob Carnein)
22 Sep-10:14:32 Re: someone told me this is what happens to mud at the bottom of a lake (Vic Rzonca)
22 Sep-08:12:37 Re: the mim museum in beirut, lebanon (Mim Museum)
22 Sep-04:26:22 Re: exchange of minerals. I'm from ukraine. (Hereiam)
22 Sep-04:01:14 Re: collection of manuel mesa (Manuel Mesa)
22 Sep-03:03:15 Re: exchange of minerals. I'm from ukraine. (Hereiam)
22 Sep-02:00:57 Exchange of minerals. I'm from ukraine. (Hereiam)
21 Sep-18:11:48 Re: need help identifying this rock (Gone Fishing)
21 Sep-18:10:17 Need help identifying this rock (Gone Fishing)
21 Sep-15:27:52 Re: collection of michael shaw (Crosstimber)
21 Sep-12:55:22 Re: denver gem and mineral show, 2017. spann style. (Tobi)
21 Sep-08:26:00 Re: someone told me this is what happens to mud at the bottom of a lake (Woody Thompson)
21 Sep-08:18:55 Re: favourite topazes? (James)
21 Sep-07:09:49 Re: favourite topazes? (Tony)
21 Sep-04:38:28 Re: collection of manuel mesa (Manuel Mesa)
20 Sep-23:07:44 Re: concrete or pumice (Alex D.)
20 Sep-22:13:45 Re: denver gem and mineral show, 2017. spann style. (Gail)
20 Sep-22:09:04 Re: denver gem and mineral show, 2017. spann style. (Gail)
20 Sep-22:05:05 Re: denver gem and mineral show, 2017. spann style. (Gail)
20 Sep-19:17:39 Re: how common is pyrite disease? (Pete Richards)
20 Sep-19:02:03 Re: how common is pyrite disease? (Protium)
20 Sep-18:31:49 Re: someone told me this is what happens to mud at the bottom of a lake (Bob Carnein)
20 Sep-18:20:12 Re: someone told me this is what happens to mud at the bottom of a lake (Trtlman)
20 Sep-18:11:51 Re: denver gem and mineral show, 2017. spann style. (Gail)

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
32938


The time now is Sep 22, 2017 15:41

Search for a textSearch for a text   

A general guide for using the Forum with some rules and tips
Interesting crystal
  
  Index -> FOR BEGINNERS: What is it? Where is it from?
Like
3


View previous topic :: View next topic  
Author Message

rmawhorter




Joined: 11 May 2017
Posts: 1
Location: BC

View user's profile

Send private message

PostPosted: May 11, 2017 23:03    Post subject: Interesting crystal  

Greetings all,
As a newbie to minerology I don't really know where to start with this. I got the Audubon Society Field Guide to Rocks and Minerals from the library but was unsuccessful in identifying this specimen. When I tried googling some of the minerals they result in such a wide range of images that I'm not sure how to even approach identifying specimens. I took some pictures of one my rocks. Could you help me identify it?

I took these pictures at different angles. On one of the pictures you can see what I'm guessing are some pyrite flecks. I tried what I could to test the hardness. I was able to scratch copper but not glass or quartz. I found this in what was probably someone's discarded rock collection that we found on a property that we were renting so there's no telling where it came from.



IMG_20170511_184927.jpg
 Description:
unknown
5cm
 Viewed:  874 Time(s)

IMG_20170511_184927.jpg



IMG_20170511_185020.jpg
 Description:
unknown
5cm
 Viewed:  871 Time(s)

IMG_20170511_185020.jpg



IMG_20170511_185134.jpg
 Description:
unknown
5cm
 Viewed:  877 Time(s)

IMG_20170511_185134.jpg


Back to top
Reply to topic Reply with quote
Like
   

Volkmar Stingl




Joined: 23 Sep 2012
Posts: 76
Location: Innsbruck

View user's profile

Send private message

PostPosted: May 11, 2017 23:26    Post subject: Re: Intersting crystal  

This is calcite.
Back to top
Reply to topic Reply with quote
Like
1
   

Matt_Zukowski
Site Admin



Joined: 10 Apr 2009
Posts: 575
Location: Alaska


Access to the FMF Gallery title=

View user's profile

Send private message

PostPosted: May 12, 2017 00:27    Post subject: Re: Intersting crystal  

If you want to confirm that it is calcite, and hopefully have some fun with some experiments, you can test the rock for hardness and solubility in an acid. For a hardness test you can try to scratch the rock with your fingernail (hardness 2.5), a copper penny (hardness 3), and a nail (hardness 5.5). Calcite has a harness of 3 so if you can't scratch it with your fingernail, find it difficult to scratch with a penny, and can scratch it with a nail, then you have material about the hardness of calcite.

Calcite is a carbonate that is particularly reactive with an acid. The best acid to use for this test is dilute HCl or muriatic acid (~10%). If you put a bit of calcite in this acid it will "fizz" readily. You can use a weaker acid called acetic acid (which is what vinegar is) to test calcite, but because it is a weaker acid you may need to crush a small bit of powder from your specimen to test (crushing increases the surface area of the material which helps speed the reaction) and/or heat the vinegar (hot vinegar reacts more vigorously than cold vinegar). Geologists carry around a small bottle of dilute HCl with them to test for calcite (and some other carbonates) when out in the field. Tums antacid tablets are made out of crushed calcite - they react with (neutralize) acid in your gut which helps with indigestion.
Back to top
Reply to topic Reply with quote
Like
2
   
Display posts from previous:   
   Index -> FOR BEGINNERS: 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 2006-2017


Powered by FMF