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
25 Jan-15:05:10 Re: hester diamond auction (James Catmur)
25 Jan-14:54:30 Re: hester diamond auction (Alfredo)
25 Jan-13:04:39 Re: chromium in jewels (Lluis)
25 Jan-12:57:09 Chromium in jewels (Tom Mazanec)
25 Jan-10:18:47 Re: hester diamond auction (John S. White)
25 Jan-09:56:07 Re: hester diamond auction (John Betts)
25 Jan-09:49:49 Re: hester diamond auction (John Betts)
25 Jan-08:34:28 Re: hester diamond auction (Carles Millan)
25 Jan-07:13:35 Re: hester diamond auction (James Catmur)
25 Jan-04:13:39 Re: the mizunaka collection - quartz (Am Mizunaka)
25 Jan-00:36:39 Hester diamond auction (Matt_zukowski)
24 Jan-21:30:06 Stream gravel quartz from howard county maryland (Jim Wilkinson)
24 Jan-20:13:14 Re: help identifying rock needed! thank you! (Baedirin)
24 Jan-19:53:59 Re: help identifying rock needed! thank you! (Pete Richards)
24 Jan-19:37:14 Help identifying rock needed! thank you! (Baedirin)
24 Jan-14:04:52 Re: collection of sante celiberti (Sante Celiberti)
24 Jan-10:38:24 Re: collection of annemieke en rob schnerr (Rob Schnerr)
23 Jan-15:33:40 Re: mysterious red pyramids in mexican opal (Amir Akhavan)
23 Jan-14:06:49 Re: collection of firmo espinar (Firmo Espinar)
23 Jan-09:34:11 Re: mysterious red pyramids in mexican opal (Michael Shaw)
22 Jan-22:14:41 Re: mysterious red pyramids in mexican opal (Ahallenbeck)
22 Jan-22:12:43 Re: mysterious red pyramids in mexican opal (Ahallenbeck)
22 Jan-10:46:19 Re: collection of michael shaw (Michael Shaw)
22 Jan-01:12:29 The mizunaka collection - quartz (Am Mizunaka)
21 Jan-15:12:48 Re: a mineralogical trip through italy by sante celiberti (Sante Celiberti)

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
77692


The time now is Jan 26, 2021 03:57

Search for a textSearch for a text   

A general guide for using the Forum with some rules and tips
The information provided within this Forum about localities is only given to allow reference to them. Any visit to any of the localities requires you to obtain full permission and relevant information prior to your visit. FMF is strictly against any illicit activities related to collecting minerals.
Help identifying unique rock
  
  Index -> What is it? - Where is it from?
Like


View previous topic :: View next topic  
Author Message

DaveP79




Joined: 03 Jan 2021
Posts: 4
Location: Cape Cod

View user's profile

Send private message

PostPosted: Jan 03, 2021 16:48    Post subject: Help identifying unique rock  

Hello,

Looking for help in identifying this rock due to its unique appearance. Apologies in advance, as I am very much a beginner, so cannot identify luster, hardness, etc. However, attached are a few photos. Additionally, this rock is light reddish-brown in color, seems to be very hard (can scratch it with a metal screwdriver but it doesn’t flake), and has a dark gray vein running through it (as can be seen in the bottom right of the pic). I found it on an ocean beach in Massachusetts. The underside of the rock is also shown and has some interesting textures.

Thanks,

Dave



5093CE86-55E3-418A-B3EA-6E36C1694600.jpeg
 Description:
 Viewed:  785 Time(s)

5093CE86-55E3-418A-B3EA-6E36C1694600.jpeg



63894DC9-195D-4367-A5A7-CFC976F5A926.jpeg
 Description:
 Viewed:  784 Time(s)

63894DC9-195D-4367-A5A7-CFC976F5A926.jpeg


Back to top
Reply to topic Reply with quote
Like
   

Peter Megaw
Site Admin



Joined: 13 Jan 2007
Posts: 905
Location: Tucson, Arizona


Access to the FMF Gallery title=

View user's profile

Send private message

PostPosted: Jan 03, 2021 17:06    Post subject: Re: Help identifying unique rock  

Tough call....not much information to work from other than it looks fairly homogeneous with minor fractures.The beaches of Massachusetts are mostly glacial dumps composed of rocks ripped up and transported by the continental glaciers that melted leaving Cape Cod, Long Island etc as their "terminal moraines"...think of the pile left in front of a dozer blade when the operator knocks off for lunch. And the scrapings can come from anywhere upglacier between that beach and the North Pole. Even if you identify what it's made of you won't know where it's from.

Call it a "glacial erratic" and enjoy it as a cool looking rock in your garden.

If you want to be more technical, we geologists have a fall back category for this sort of thing FRDK.. stands for Funny Rock Don't Know.

Keep looking...there's good stuff out there

_________________
Siempre Adelante!
Back to top
Reply to topic Reply with quote
Like
   

Peter Megaw
Site Admin



Joined: 13 Jan 2007
Posts: 905
Location: Tucson, Arizona


Access to the FMF Gallery title=

View user's profile

Send private message

PostPosted: Jan 03, 2021 17:08    Post subject: Re: Help identifying unique rock  

Forgot to mention that those parallel grooves on the smooth surface were probably made by the glacier as it was dragged against other rocks

In short...what has happened to this rock is more interesting than what it is!!

_________________
Siempre Adelante!
Back to top
Reply to topic Reply with quote
Like
   

DaveP79




Joined: 03 Jan 2021
Posts: 4
Location: Cape Cod

View user's profile

Send private message

PostPosted: Jan 03, 2021 19:28    Post subject: Re: Help identifying unique rock  

Hi Peter,

Thanks for the help and the insight. Maybe not the most exciting find, but it’s definitely piqued my interest in searching for some more “FRDKs” in this area. Looking forward to learning more about geology in the Cape and in general!

Best,

Dave
Back to top
Reply to topic Reply with quote
Like
   

Peter Megaw
Site Admin



Joined: 13 Jan 2007
Posts: 905
Location: Tucson, Arizona


Access to the FMF Gallery title=

View user's profile

Send private message

PostPosted: Jan 03, 2021 19:34    Post subject: Re: Help identifying unique rock  

Welcome to the Monkey House...
_________________
Siempre Adelante!
Back to top
Reply to topic Reply with quote
Like
   

Peter Megaw
Site Admin



Joined: 13 Jan 2007
Posts: 905
Location: Tucson, Arizona


Access to the FMF Gallery title=

View user's profile

Send private message

PostPosted: Jan 03, 2021 19:35    Post subject: Re: Help identifying unique rock  

There's a really good beginners book on the geology of Cape Cod...I know where my copy is...at my sister's in Falmouth

I'll see if I can get you a title

_________________
Siempre Adelante!
Back to top
Reply to topic Reply with quote
Like
   

Peter Megaw
Site Admin



Joined: 13 Jan 2007
Posts: 905
Location: Tucson, Arizona


Access to the FMF Gallery title=

View user's profile

Send private message

PostPosted: Jan 03, 2021 19:39    Post subject: Re: Help identifying unique rock  

Just Google "Cape Cod geology USGS" it'll take you right to the paper
_________________
Siempre Adelante!
Back to top
Reply to topic Reply with quote
Like
   

DaveP79




Joined: 03 Jan 2021
Posts: 4
Location: Cape Cod

View user's profile

Send private message

PostPosted: Jan 03, 2021 20:11    Post subject: Re: Help identifying unique rock  

Sounds like a must have for the Cape. I’ll look it up. Thanks for the recommendation.
Back to top
Reply to topic Reply with quote
Like
   

Pete Richards
Site Admin



Joined: 29 Dec 2008
Posts: 723
Location: Northeast Ohio


Access to the FMF Gallery title=

View user's profile

Send private message

PostPosted: Jan 03, 2021 21:13    Post subject: Re: Help identifying unique rock  

It's quite a bit of a reach, just from those photographs, but the texture of the object suggests bone. I suggest you get in touch with a vertebrate paleontologist who knows the paleofauna of the Cape Cod area to see if it might be a fossil of some sort. The hardness is appropriate for fossilized bone. There is also a suggestion of bilateral symmetry (suggestive, not diagnostic).
_________________
Collecting and studying crystals with interesting habits, twinning, and epitaxy
Back to top
Reply to topic Reply with quote
Like
   

Pete Modreski
Site Admin



Joined: 30 Jul 2007
Posts: 690
Location: Denver, Colorado


Access to the FMF Gallery title=

View user's profile

Send private message

PostPosted: Jan 04, 2021 10:17    Post subject: Re: Help identifying unique rock  

That is all very good advice about your rock that you received from Pete Megaw.

Likewise, Pete Richards' suggestion is good--I also thought that its shape "might" suggest some kind of fossil, though, the little (quartz probably) veinlets running through it would argue, probably not really a fossil.

As you will learn if you try to study and learn about rocks some more, a very fine-grained, fairly hard rock can be quite hard to identify, even for "any good geologist"! There are many, though very different in origin and nature, kinds of such rocks that can appear very similar, and lacking any real obvious distinguishing characteristics: quartzite, sandstone, meta-siltstone, even a very fine-grained granite. The fact that you say it's pretty hard seems to rule out one other possibility, limestone. "In theory", if your rock is quartzite, you should NOT be able to scratch it at all with a knife or other sharp tool. But there is a continuous gradation between quartzite, sandstone, siltstone, argillite, and others (degree of purity of quartz of which it is composed vs. content of clay and other soft minerals, plus degree of metamorphism, all resulting in a range of possibly hardness). This all makes geology so interesting, and complex! You may never get a completely satisfactory, positive answer as to "exactly what this rock is"!

Best of luck with this & your future "interesting rock" observations,

Another Pete M. (Modreski)
Back to top
Reply to topic Reply with quote
Like
   

DaveP79




Joined: 03 Jan 2021
Posts: 4
Location: Cape Cod

View user's profile

Send private message

PostPosted: Jan 04, 2021 21:05    Post subject: Re: Help identifying unique rock  

Thank you for your help, gentlemen, and for providing a bit of informal education to this very novice rock hunter. I will certainly try to find a paleontologist and get his/her take. Otherwise, happy to relegate it to the confines of my garden and find more interesting rocks to keep it company!
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 2006-2021


Powered by FMF