What is This?

[HayJude69]

Good Evening, This rock was found in New Jersey by one of my farmer relatives and has been in my family for as long as I can remember. It went back and forth to Geology class as a "show and tell" rock by all the children. No one could "tell" or identify what type of rock it is. The rock is covered in a rainbow of various colors. Can anyone identify this rock?
Thanks!
Jude

 

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[Back-of-the-boat]

It has colors you would find in peacock ore but that is where the similarities end. The structure of it is really strange, but it is very cool looking.

 

[MountOlymp]

Good Evening, This rock was found in New Jersey by one of my farmer relatives and has been in my family for as long as I can remember. It went back and forth to Geology class as a "show and tell" rock by all the children. No one could "tell" or identify what type of rock it is. The rock is covered in a rainbow of various colors. Can anyone identify this View attachment 2006098View attachment 2006097rock?
Thanks!
Jude

Slag

 

[Indian Steve]

Looks like iridescent hematite.

 

[Red-Coat]

Looks like iridescent hematite.

Agree! Also known as 'rainbow' hematite. It's usually hematite in admixture with goethite.

Your (nice) specimen is natural. but most of what passes for 'irirdescent hematite' as polished material in rock&gem outlets is man-made.

Welcome to Tnet.

 

[traveller777]

Agree! Also known as 'rainbow' hematite. It's usually hematite in admixture with goethite.

Your (nice) specimen is natural. but most of what passes for 'irirdescent hematite' as polished material in rock&gem outlets is man-made.

Welcome to Tnet.

Pretty good analysis without knowing hardness or weight. Impressive.

 

[Red-Coat]

Pretty good analysis without knowing hardness or weight. Impressive.

Don't really need that information when the crystal structure is so obvious.

 

[traveller777]

Don't really need that information when the crystal structure is so obvious.

you are smarter than me. good job

 

[Back-of-the-boat]

I never knew that hematite had that look but after seeing it in pictures on the web I agree and funny thing is I have some in a curio cabinet that I found in an old gold mine I was exploring. I thought it was a type of peacock ore but now I believe it is iridescent hematite.

 

[HayJude69]

It has colors you would find in peacock ore but that is where the similarities end. The structure of it is really strange, but it is very cool looking.

What is peacock ore? Can I sell this rock?

 

[Red-Coat]

What is peacock ore? Can I sell this rock?

Peacock ore is principally the mineral "bornite", a complex of copper and iron sulphides that's red-brown on fresh surfaces and often weathers and tarnishes to iridescent colours after exposure... but that isn't what you have. It has the wrong crystal habit for bornite... but the right crystal habit for hematite. Rainbow hematite acquires its surface colour from a very thin deposition of an aluminium phosphate.

Neither bornite nor rainbow hematite have any particular value in 'specimen-size' pieces and would cost you only a few dollars from a rock&gem shop. Both can be rather pretty and popular with collectors though.

 

[crashbandicoot]

Cool!

 

[HayJude69]

Peacock ore is principally the mineral "bornite", a complex of copper and iron sulphides that's red-brown on fresh surfaces and often weathers and tarnishes to iridescent colours after exposure... but that isn't what you have. It has the wrong crystal habit for bornite... but the right crystal habit for hematite. Rainbow hematite acquires its surface colour from a very thin deposition of an aluminium phosphate.

Neither bornite nor rainbow hematite have any particular value in 'specimen-size' pieces and would cost you only a few dollars from a rock&gem shop. Both can be rather pretty and popular with collectors though.

Thank you so much for this information! I really appreciate your response!

 

[tedcunningham]

Good Evening, This rock was found in New Jersey by one of my farmer relatives and has been in my family for as long as I can remember. It went back and forth to Geology class as a "show and tell" rock by all the children. No one could "tell" or identify what type of rock it is. The rock is covered in a rainbow of various colors. Can anyone identify this View attachment 2006098View attachment 2006097rock?
Thanks!
Jude

Streak test, magnetic test, moh hardness, u.v. light effect, specifig gravity, would help id. My guess is that is a metamorphic rock that just recently ended its rock cycle, and its tiny fragments previously destroyed by fire are begining to eggregate together and form a new metamorphic rock. Is it a dirty burnt pieve of foliated shist? Goodluck

 

[Blackfoot58]

Good Evening, This rock was found in New Jersey by one of my farmer relatives and has been in my family for as long as I can remember. It went back and forth to Geology class as a "show and tell" rock by all the children. No one could "tell" or identify what type of rock it is. The rock is covered in a rainbow of various colors. Can anyone identify this View attachment 2006098View attachment 2006097rock?
Thanks!
Jude

Resembles Fayalite, but the surface structure might be wrong. It can exhibit many colors, yellow, grey, black, green, brownish-red. Just a wild guess on my part. I hope you find out.