Black rocks on the beach?

[Starlight80]

Hello! I'm new here and really don't know much about rocks, so sorry if these are nothing special

We found 2 of these rocks on the beach today, and after spending a while looking, we couldn't find more of them. They look a lot darker than they are in the photos, and at first we thought they could be coal or something, but they're too heavy. They're also very glittery and glassy in places Any ideas? Thanks.

 

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[timekiller]

It's surely got a crystal structure to it.Maybe Black Tourmaline. I've got some good size pieces somewhere around here.
Take Care,
Pete,

 

[Dig-m-Deep]

It looks like slag glass from a blast furnace

 

[timekiller]

All my bigger pieces are in my 150 gal. aquarium. But I did have some smaller ones laying around.
Anyway forgot to welcome you to T-net SO WELCOME.
Pete,

 

[Starlight80]

Ahh cool! That's exactly what it looks like. Thank you!

 

[timekiller]

I had to check myself because I've never heard of it being found over there in the UK.But it is not out of question I don't guess.Were you around Cornwall??
http://www.crystalshop.co.uk/factsheets/Tourmaline-factsheet.html
Take Care,

 

[High Plains Digger]

You have some nice garnets there, Timekiller. And your question about Cornwall is a good one. Could be sphalerite/galena and whatever else mixed up, but I am not familiar with what occurs with tin. The fluorite in the area could mean the galena is there.

 

[Breezie]

Beautiful aquarium Pete! Breezie

 

[timekiller]

You have some nice garnets there, Timekiller. And your question about Cornwall is a good one. Could be sphalerite/galena and whatever else mixed up, but I am not familiar with what occurs with tin. The fluorite in the area could mean the galena is there.

OOOOps, Wrong bag that's what happens when your color blind. Here you go black tourmaline.(for sure this time )

 

[Starlight80]

I had to check myself because I've never heard of it being found over there in the UK.But it is not out of question I don't guess.Were you around Cornwall??
http://www.crystalshop.co.uk/factsheets/Tourmaline-factsheet.html
Take Care,

I found them Winchelsea Beach, near East Sussex, so quite far from Cornwall It is a bit odd I guess.

 

[High Plains Digger]

You have some nice tourmaline there, Timekiller. Does this seem like groundhog day or what? The striations are very indicative of tourmaline--do you see those on the subject? But I do have crystals without the striations, so I suppose it is not mandantory. But tourmaline shouldn't ring a detector. The subject has to have a lot of mineralization. Those square faces look like galena to me, I don't think tourmaline will fracture in square blocks like that.

There is a guy out here that takes some "exotic" rocks and leaves them on the gravel bars in the So. Platte. When a piece of sliced "moss" agate is found, you know it is salted. The poster has to tell us about some of the geology of the area to help, and if there are only 2 rocks like this there, then one has to wonder. Can you do a streak test on it? Go to tile world and buy 1 bath tile, unglazed on the back, and scratch one of those square faces across it. I believe (memory value -3) that galena has a grey streak, but we can verify that later. I don't know what galena looks like when it "rusts" but it could be more black and less silvery.

 

[High Plains Digger]

Oops, sorry, I was looking at Timekiller's first sample, which looks a lot like galena. But do a streak test anyway. Find a place on the rock that will touch the tile yet seems to be as "pure" of black material as possible.

 

[Starlight80]

Thanks for the replies. I'll try and get hold of a tile tomorrow. Here are some photos of the beach. We didn't search that hard, but these two seemed to be on their own and different to the others. The beach is on the south east coast, about 20 miles from Dover.

 

[timekiller]

You have some nice tourmaline there, Timekiller. Does this seem like groundhog day or what? The striations are very indicative of tourmaline--do you see those on the subject? But I do have crystals without the striations, so I suppose it is not mandantory. But tourmaline shouldn't ring a detector. The subject has to have a lot of mineralization. Those square faces look like galena to me, I don't think tourmaline will fracture in square blocks like that.

There is a guy out here that takes some "exotic" rocks and leaves them on the gravel bars in the So. Platte. When a piece of sliced "moss" agate is found, you know it is salted. The poster has to tell us about some of the geology of the area to help, and if there are only 2 rocks like this there, then one has to wonder. Can you do a streak test on it? Go to tile world and buy 1 bath tile, unglazed on the back, and scratch one of those square faces across it. I believe (memory value -3) that galena has a grey streak, but we can verify that later. I don't know what galena looks like when it "rusts" but it could be more black and less silvery.

Here is were I got the pic. you are speaking of.But I see others that look like it as well if broken in the right place.
Take Care,
Pete,
http://www.stevesearthlybounty.com/gallery_vi

 

[High Plains Digger]

Nice site. But wow, I have a whole box of purple stained aragonite just like what he is offering for $99. He doesn't mention what the purple staining is or how it got there, which is an interesting story in itself.

I am still not convinced on tourmaline, as much as that is my favorite stone. It just doesn't look right, and I have several hundred pounds of massive, slightly chrystaline tourmaline. The impurities don't seem quite right. Sorry, no sale on tourmaline yet.

 

[Starlight80]

Hello again. We tried the streak test, and it didn't really leave a mark at all...

 

[timekiller]

Hello again. We tried the streak test, and it didn't really leave a mark at all...

Yea no big surprise to me,it's just a basic test that can be done.But will say by doing it & you say I guess it left a white streak, then black tourmaline can't be ruled out as that is what it would leave for a streak test.
http://www.scribd.com/doc/46120032/...ock-of-the-Month-Build-a-Kids-Rock-Collection
Also here is a great site for all sorts of minerals.Gives crystal forms of minerals, hardness,Etc.
http://webmineral.com/specimens/gallery.php?st=1&init=A

 

[High Plains Digger]

I thought I would add a couple of tourmaline samples.

 

[Starlight80]

Thanks for the photos.

We've been doing a bit of research and came up with a theory, perhaps they could be meteorites? There are slight burnt bits in places over the rocks, but I didn't think much of it at first, and now we've noticed they smell a bit too. The Perseid meteor shower is taking place at the moment, so that would explain the odd location? Also, we found an article in the news from a couple of years ago where a child found a meteorite.

They do look quite similar. This is just guesswork, as like I've said, I really don't know much about this.

 

[High Plains Digger]

I've lost track--did we say this rock was magnetic?

Someone on the forum on one of the other "black rocks" said if you think it is a meteorite, it's not. Generally true. But I am almost certain that this rock hasn't been through the earth's atmosphere and heated to 2000+ degrees on it's surface. No fusion crust.

Your last photo looks different than your close ups, but maybe not. I have just one thing to say: