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
20 Jan-23:21:46 Re: any help with id? (Alfredo)
20 Jan-19:22:32 Any help with id? (Jedorton)
20 Jan-14:32:00 Re: help with mineral found, san rocendo canyon, mexico (Yazzyenna)
20 Jan-02:00:25 Re: collecting focuses and how they can change (Andreas Gerstenberg)
19 Jan-23:46:36 Re: a bit on the economics of being a mineral dealer (Bob Kerr)
19 Jan-23:26:28 Re: help with mineral found, san rocendo canyon, mexico (Peter Megaw)
19 Jan-23:17:14 Help with mineral found, san rocendo canyon, mexico (Yazzyenna)
19 Jan-18:13:19 Re: collecting focuses and how they can change (Don Lum)
19 Jan-15:08:21 Re: a bit on the economics of being a mineral dealer (Pierre Joubert)
19 Jan-14:00:11 Re: andreas gerstenberg collection (Tobi)
19 Jan-13:56:49 Re: favourite fluorites? (Tobi)
19 Jan-13:39:16 Re: a bit on the economics of being a mineral dealer (Peter Lemkin)
19 Jan-13:14:06 Re: a bit on the economics of being a mineral dealer (Pierre Joubert)
19 Jan-12:26:51 Re: locality for this probable natrolite (?) specimen? (John Medici)
19 Jan-12:13:41 Re: a bit on the economics of being a mineral dealer (Pete Modreski)
19 Jan-11:43:30 Re: unsure about japan law twin, please help. (Roger Warin)
19 Jan-11:38:59 Re: andreas gerstenberg collection (Jordi Fabre)
19 Jan-11:19:56 Re: andreas gerstenberg collection (Andreas Gerstenberg)
19 Jan-07:29:09 Re: franjungle collection (Franjungle)
19 Jan-00:06:45 Re: locality for this probable natrolite (?) specimen? (Pete Modreski)
18 Jan-23:34:38 Re: unsure about japan law twin, please help. (Bob Morgan)
18 Jan-20:52:32 Re: locality for this probable natrolite (?) specimen? (Pete Richards)
18 Jan-20:32:44 Re: locality for this probable natrolite (?) specimen? (Rweaver)
18 Jan-20:02:27 Re: locality for this probable natrolite (?) specimen? (John Medici)
18 Jan-19:09:28 Locality for this probable natrolite (?) specimen? (Pete Modreski)

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
38186


The time now is Jan 21, 2018 07:43

Search for a textSearch for a text   

A general guide for using the Forum with some rules and tips
What is it? Chalcedony?
  
  Index -> FOR BEGINNERS: What is it? Where is it from?
Like
1


View previous topic :: View next topic  
Author Message

BHmineral




Joined: 14 Dec 2012
Posts: 29
Location: Diamantina -MG (Brasil)

View user's profile

Send private message

PostPosted: Jan 25, 2017 10:38    Post subject: What is it? Chalcedony?  

Hi,

What is it? Chalcedony in coral? It is from Tampa Bay, Florida - USA

Size: 6 x 4,5 cm

Thank you.



IMG_3625.JPG
 Locality:
Florida, USA
 Description:
 Viewed:  1715 Time(s)

IMG_3625.JPG


Back to top
Reply to topic Reply with quote
Like
1
   

James
Site Admin



Joined: 14 Sep 2006
Posts: 533
Location: Cambridge


Access to the FMF Gallery title=

View user's profile

Send private message

PostPosted: Jan 25, 2017 10:48    Post subject: Re: What is it? Chalcedony?  

Could you please do a hardness test?

http://www.mineral-forum.com/message-board/viewtopic.php?p=19487#19487

If it is chalcedony it should scratch glass

James
Back to top
Reply to topic Reply with quote
Like
   

kushmeja




Joined: 28 Jul 2014
Posts: 189
Location: New Jersey

View user's profile

Send private message

PostPosted: Jan 25, 2017 10:50    Post subject: Re: What is it? Chalcedony?  

Yes - this is fossilized coral that was replaced by quartz/chalcedony. It looks similar to the the material from the Tampa Bay area, but could possibly be from another area of FL or southern GA.
Back to top
Reply to topic Reply with quote
Like
   

Bob Carnein




Joined: 22 Aug 2013
Posts: 79
Location: Florissant, CO

View user's profile

Send private message

PostPosted: Jan 25, 2017 10:51    Post subject: Re: What is it? Chalcedony?  

It is chalcedony. These "geodes" often fill or replace fossil corals from the Oligocene (?) Hawthorn Group, on Tampa Bay.
Back to top
Reply to topic Reply with quote
Like
   

Bob Harman




Joined: 06 Nov 2015
Posts: 290
Location: Indiana


Access to the FMF Gallery title=

View user's profile

Send private message

PostPosted: Jan 25, 2017 11:20    Post subject: Re: What is it? Chalcedony?  

This is a long time well recognized deposit of fossilized coral replaced by quartz var chalcedony. They are from Tampa Bay, Florida as this one is. In my opinion, no testing is necessary on classic pieces as this one is. BOB
Back to top
Reply to topic Reply with quote
Like
   

markbeckett




Joined: 06 Oct 2016
Posts: 41
Location: Cornwall


Access to the FMF Gallery title=

View user's profile

Send private message

PostPosted: Jan 25, 2017 13:38    Post subject: Re: What is it? Chalcedony?  

How Amazing!
_________________
Ex Camborne School of Mines
Grad - B.Eng. Geol. (1993)

'if you see a strange hill, go and prospect there'...(KFG Hosking)
Back to top
Reply to topic Reply with quote
Like
   
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 2006-2018


Powered by FMF