FMF - Friends of Minerals Forum, discussion and message board

[Volan]

Hello everyone!
My name is Andrei and this is my first topic started on this forum, and will definitely won't be the last one :)
I recently went for the first time to Whitby, trying to find some fossils..
I got more rocks than fossils and possible a chunk of fossil wood.

However, I am baffled about one specific BLUE colored rock and I need a second opinion as my knowledge is far from even an amateur level.

So.. here are the details:
Location : Robin Hood Bay (was on shore, and not embedded)
It looks like a soft rock but I tried to cut a small piece with a Dremel tool and it looks quite strong. I tried to polish the surface with a wire wheel (gold color) and the rock is polishing very easy looking like a gold/chrome color.
I tried to split the rock with a chisel and a hammer as it had a crack all the way around. First attempts ended in this rock leaving a groove in the concrete pavement.
And now comes the fun part : after I managed to split the rock a VERY strong smell of sulfur came out (I actually had to leave the rock outside).
I mention that the rock had no smell when hit by the hammer or when I tried to cut and polish. The smell diminished over night but it still stinks.

After all my research I ended up thinking it's some sort of industrial slag. And I hope it is not radioactive :)) or toxic. What do you think ?

Edit : i have some household chemicals based on acid's. One contains Formic Acid (Kilrock - gel) , one Hydrochloric Acid (Harpic x10) , and one Phosphoric Acid (Kilrock descaler) which one should I use for the acid test ?

[Scot Krueger]

This looks like a small cobble of slightly altered vesicular basalt. It started life as a black lava flow with lots of bubbles. Over time, groundwater allowed the bubbles to become lined with some secondary minerals. The rock was buried enough to be slightly metamorphosed, and the blue color is likely from microscopic clays and/or chlorite. As for the smell, that is impossible to assess from a photo. But I can think of 3 likely possibilities. The first, the white mineral in the holes has sulfur in it, causing the smell when exposed. Second, some of the crud which is on the surface, and obviously invaded deep into the cracks, is some fetid organic matter which you exposed by cracking it open. And third, this might have been exposed to hydrocarbons at some point (petrol from an auto, lighter fluid from a beach fire, natural or manmade oil spill) which seeped into the cracks and was finally exposed to the air when you broke it. Once you have let it air out long enough that it does not smell, it should no longer pose a health hazard.

[Tracy]

[stoned]

I wouldn't handle it without a HazMat suit...

[Tracy]

[Pete Modreski]

He was joking about the hazmat suit, Tracy.

Andrei, though the rocks looks just like a vesicular basalt, it might also be some type of industrial slag, containing sulfur, or iron sulfides that have oxidized to produce the sulfur smell. Such slag often contains gas bubbles, and can contain sulfur compounds.

Pete

[alfredo]

I fully agree with Tracy. Sulphur (or more accurately sulphur oxides or hydrogen sulphide rather than elemental sulphur itself) has a very strong smell, so it takes only a tiny amount in a rock to notice it. No danger to you, your pets, your kids... But don‘t store it next to your silverware because sulfur makes silver tarnish.

[Tracy]

Thank you Pete and thank you Alfredo, and apologies to Stoned for sounding snitty. Text is often emotionless and I missed the joke.

I think for the new year/decade it's time for me to climb down off my soapbox and leave the focus of this forum on minerals (where it belongs), not health and safety. I would rather people were overly cautious than the opposite, even if I don't always understand the (in my opinion) misperception that there is any meaningful health hazard potential associated with handling specimens (radioactivity and dust-generating activities like extracting and trimming or cutting excepted). Don't eat, snort, or rub on skin - to each their own after that.

A happy 2020 to everyone!
Tracy

[Volan]

Thank you for your answers ! Great help ! I will keep it aside for the moment and try to "explore" it more.
I also have couple of rocks from the same place and some resemble like coprolite fossil, plus other unknown (to me) rocks.
I will post a photo when i can make some clear ones.

Cheers!

[colin robinson]

Industrial slag. Millions of tons of it ended up in the north sea after being dumped from the iron and steel works on Teesside. Longshore drifting has carried it south and it can be found all along the Yorkshire coast and probably much further afield.

[stoned]

"and apologies to Stoned for sounding snitty. Text is often emotionless and I missed the joke. "

No apologizes needed Tracy, I don't think you were snitty at all. I was in a hurry when I left that, I should have put a smiley face at the end... :-)

Speaking of health and safety...

since I know I may have a stone or two that has been irradiated by man (thinking of my smoky quartz), I wonder if I had a Geiger counter, how much residual is left over? Anything for me to worry about?

It wouldn't be allowed to be sold here I would think if it was radio active.

[Jordi Fabre]

[stoned]

What I meant was by saying "here".... as in the USA.

[Tracy]

"Irradiation" means receipt of energy from radioactive emissions/decay. The radioactivity is inherent to the material emitting the energy, it doesn't transfer to the irradiated object. If it did, you would become radioactive after getting an x-ray. :)

Your smoky quartz (which might have been naturally irradiated by the sun) is nothing to worry about.

Cheers
Tracy

[stoned]

Good to know Tracy, was worried I would start to glow if I kept it too close for too long. Thanks for putting my mind at ease. I learn a lot here, that's for sure!