Please help me identify this unique looking rock.

[RocksLover]

Hello Admins and all members. I need your help in identifying this rock I recently found. I live in southern NJ, its about 30 lbs, and its been cleaned. When doing a google image search the two possibilities were Antlerite and Cuprite. But those characteristics dont match the pics of my rock. Thank you all in advance for your assistance in trying to help me figure this out. I have been collecting rocks and fossils since a young child but have never seen a rock quite like this one before. I dont know what it is.

 

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[old digger]

Welcome to tnet!
Hopefully someone from your area can help you with your rock specimen.

 

[RocksLover]

Hello old digger nice to meet you. This rock has been frustrating me cause I cant figure out what it is. I posted pics on a rock forum on FB and never heard anything back except for 2 likes. Im really hoping someone can help me identify this rock. Have you ever seen anything like this before?

 

[old digger]

I am not an authority on rocks in your area, but your specimen appears to be some type of a quartz mineral with a greenish tint. There are some better qualified members here on tnet that I am sure will help you figure this one out.

 

[mollyk927]

Olivine? Just a guess.

 

[RocksLover]

Hi mollyk927. Thank you so much for the response. I looked up Olivine and it says its the gemstone Peridot. This rock I have is huge and its covered with these gems on 3 sides. I wonder if this really is Olivine? Again thank you for your response and I will hopefully hear from some other members what they think it is. Stay Safe & Be Well.

 

[Kray Gelder]

Olivine is a common mineral found in volcanic material. Your rock looks like volcanic tuff/ash. The color is right for it. Nice specimen!

 

[RocksLover]

Thank You. I wonder how much its worth any guess? I will be taking it for confirmation of what it is and an appraisal once the pandemic has slowed down.

 

[Upnorth42]

What you found is very interesting. I definitely would have made an effort to bring one like that home. It will be interesting to see what it turns out to be. Any local rock hunting clubs in your are that might be able to help? Have you done any hardness testing on it?

 

[Clay Diggins]

It resembles Forsterite (Peridot is the gem variety of Forsterite) but the color is off. Forsterite is either clear, yellow or green. I have never seen colored Forsterite without a major yellow component. Certainly Peridot doesn't have a bluish component.

The crystal forms are hard to determine from the pictures but I'm not seeing Forsterite crystal shapes or angles in the few crystals that show form. I'm thinking it might be more of a volcanic glass?

 

[fuss]

This could also be slag, There are some bubbles in the matrix and the crystals look a lot like glass. I'm not saying it is, but possible. Can you do a scratch test on the greenish crystals? and it would be very helpful if you could get some sharper close up photos.

 

[RocksLover]

Hello Upnorth42. I agree it is very interesting. I dont know but I will do a search for NJ. No I have not done any hardness testing yet. How does one go about doing a hardness test?

 

[RocksLover]

Hi Clay Diggins. To me it seems to be a light green color not blue. What is Volcanic glass? I will be taking some outdoor in the daytime and also some upclose pics and posting them soon.

 

[RocksLover]

Hi fuss. I will be taking outdoor daytime and upclose pics and posting them soon. How do I do a scratch test and with what? And what is slag?

 

[Back-of-the-boat]

These are some different ones to look at. Prasiolite ,Prehnite, Fluorite, or Spodumene. Figure out what the matrix is and you can probably narrow the possibilities down it looks like limestone or sandstone so I would find out what greenish crystals form in limestone or sandstone.

 

[RocksLover]

Hi Back-of-the-boat. Thank you for the advice. Btw Im in Southern NJ. I wonder if limestone and sandstone is found here?

 

[Clay Diggins]

Maybe it just looks blueish on the computer. Better pictures in sunlight would be helpful.

Did you find the rock in New Jersey? If so it's not volcanic. If it's actually a New Jersey native "rock" I'd be inclined to agree with fuss - it's slag.

 

[RocksLover]

Clay Diggins. Yes I will be taking upclose and outdoor sunlight pics soon. Yes I found it in NJ. What is slag? Is it worth anything if it is slag?

 

[Clay Diggins]

Slag is man made. It's is the cooled and solidified remains from industrial processes. That could be smelting, glassmaking or coal boiler waste. Some of the slag forms can be attractive and often can lead to clues about the historic activities in the area.

 

[RocksLover]

Clay Diggins. What I can say is it was found on my next door neighbors front yard buried. I was given permission to remove all rocks and bricks from her property for free. Both of our houses are lakefront properties. If I say anymore it will give away my precise location so I cannot do that. I hope this info helps. Im assuming if it is slag its not worth much. I want to get to the bottom of this mystery rock badly lol. Thanks for all of your input I will keep researching it and when the pandemic has slowed down I will be taking it somewhere to get confirmation of what it is and its value.