Unusual Black Textured Fossil or Rock

[Jmb]

My husband and I found this strange textured piece in South Jersey at the edge of the Pinelands. 

Is this a Fossil or Rock? Any information will be appreciated. Thank You

Below is what we determined so far:

Dull black, not shiny.

Smooth Brain like texture on surface.

7"  long x 1.5" wide

Not magnetic.

Does not fizzle with vinegar.

Does not flake or chip easily. 

Not porous.

 

[Fossildude19]

Welcome to the Forum.

 

Your item reminds me of a limonite nodule.  

 

So, geologic, rather than a fossil. 

Pretty interesting looking, though.  

Regards,

[ynot]

Welcome to TFF!

Can You scratch it with a knife?

Can You do a streak test. (Scratch it on unglazed porcelain for color of streak)

 

I agree that it is not a fossil. It does look like an iron mineral, but limonite is usually rust colored.

[abyssunder]

Maybe Goethite ?

Here is a long list of minerals of New Jersey.

[Rockwood]

Left field here 

I put too many spoonfuls of ovaltine in my coffee today. After a quick stir I noticed a pattern a little like this had resulted from the mixing color/densities.

Moral of story

Could be many minerals.  

[Jmb]

Thanks for all the responses, the NJ mineral list link, and the suggestions it may be a Limonite Nodule or Goethite.

I did the scratch test with a knife. The knife left a silvery mark that wiped off. No scratch indent, no chips, not even flakes.  

I also did the streak test on the non-glazed back of a porcelain tile. It left a white mark on the tile and the rock. The white mark on the rock wiped off with no scratches on the rock. 

 

PS Ovaltine in coffee sounds delicious! lol

 

 

 

[ynot]

Not scratched and no streak. Sounds like it is a piece of black chert or maybe obsidian.

Definitely not an iron mineral.

[non-remanié]

I agree with chert. I have found chert nodules in NJ with a very similar dimpled surface texture as well.

[bjkibz]

Chert makes sense -- Pinelands are almost straight-up sediment, so anything volcanic is very unlikely. My initial thought was a glauconitic concretion, but streak and hardness don't match up.