Assistance with a rock identification 2 (southwest part of the U.S.)

[C Mac]

Hello,
Could I please get assistance with a rock identification. I came across this one in the southwest part of the U.S. While I see a lot of slag from old mines, this rock appears to be something different than slag. Besides, it was the only dark colored rock I came across that day. It also appears to have grooves of some kind.

This is my second post asking for assistance with a rock identification, so just a reminder, I do historical research and at times, come across (what I consider) odd rocks that don't match anything else in the area.

Please see the attached photos and let me know your thoughts or if you have additional questions.
Thank you in advance.

 

[Tom.G]

Just a first-pass guess, details left for the more knowledgeable ones here. Is it magnetic, heavier than expected? Could me a meteorite.

 

[davenn]

I came across this one in the southwest part of the U.S.

Specifically ? ... state and area in state ?


My initial thoughts would be Basalt
There's a lot of volcanics in Arizona and a reasonable amount in New Mexico
I would have to dig through my travel pix, but did take some good photos of lava flows in NM

Dave

 

[C Mac]

Thanks for the feedback Tom and Dave,
No, not magnetic. Also, doesn't seem heavier than expected. Actually, it might seem a pinch lighter than expected, but it doesn't have any identifiable voids to air pocket - that I can see.

I believe this was also SE Arizona. Please understand that unless I take a photo at the time I come across a rock, I probably won't have specific information since I'm not out actually hunting rocks.

Now that you say, basalt, I remember seeing a topo map identifying a "cinder hill" about 40 miles SE of where I picked this up, so maybe I came across this rock after it had been previously moved? There were just no other rocks like this in the area, but it would make sense it might be basalt.

 

[davenn]

No, not magnetic. Also, doesn't seem heavier than expected. Actually, it might seem a pinch lighter than expected, but it doesn't have any identifiable voids to air pocket - that I can see.

OK :)
Being magnetic doesn't confirm a meteorite. Other tests would have to be done for that. Even basalt can show magnetic tendencies
as it often has a reasonable around 20 - 40% iron content.

I believe this was also SE Arizona. Please understand that unless I take a photo at the time I come across a rock, I probably won't have specific information since I'm not out actually hunting rocks.

that's OK, no problems ... state and area in state is a great start. As you could imagine, geology can change rapidly across a given region.
So the more accurate you are, the easier it makes to identify

Now that you say, basalt, I remember seeing a topo map identifying a "cinder hill" about 40 miles SE of where I picked this up, so maybe I came across this rock after it had been previously moved? There were just no other rocks like this in the area, but it would make it might be basalt.

that really helps narrow it down
Cinder Hills is just NE of Flagstaff. Been there a couple of times. that whole region from the Flagstaff area and right
up to the Grand Canyon is full of volcanics

awesome stuff ... I look forward to seeing your next query


Dave

 

[C Mac]

Sorry, let me provide a little clarity. I was SE of Tucson in SE Arizona when I came across this rock. SE of my location where I found this rock, close to the Arizona, New Mexico, Mexico border, is a small hill identified as "cinder hill." My bad if I made this confusing, but there is a hill in the area of Arizona, New Mexico, and the Mexican border identified as "cinder hill.." Anyway, same name as the one up in Flagstaff, but geographically in a different part of the state.

 

[davenn]

I was SE of Tucson in SE Arizona when I came across this rock. SE of my location where I found this rock, close to the Arizona, New Mexico, Mexico border, is a small hill identified as "cinder hill." My bad if I made this confusing, but there is a hill in the area of Arizona, New Mexico, and the Mexican border identified as "cinder hill.."

No Problems
I haven't been as far south as Tucson. Always wanted to get to Tombstone, AZ., just for the historical value, maybe one day.

Anyway, still plenty of volcanic outcrops around that SE area of the state, so I would expect that you would find plenty of evidence
scattered around the area


D