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 Post subject: Meteorite from the Sikote Alin fall in Russia in 1947
PostPosted: Mon May 09, 2016 8:57 pm 
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Over Mother's Day Brunch I was treated to an awesome Show and Tell from Linda and Norman Mahan, whom I first met when i was a sophomore in college. They owned a jewelry store across the street from where I worked and I spent every lunch break at their shop being a nuisance.

Now, is this pendant "out of this world" or what?
This is a shard from the Sikote Alin Meteorite which hit the planet 69 years ago and was (and is) the largest meteorite to strike Earth which was actually witnessed by humans.

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Wiki wrote:
At around 10:30 on 12 February 1947, eyewitnesses in the Sikhote-Alin Mountains, Primorye, Soviet Union, observed a large bolide brighter than the Sun that came out of the north and descended at an angle of about 41 degrees. The bright flash and the deafening sound of the fall were observed for 300 kilometres (190 mi) around the point of impact not far from Luchegorsk and approximately 440 km (270 mi) northeast of Vladivostok. A smoke trail, estimated at 32 km (20 mi) long, remained in the sky for several hours.

As the meteor, traveling at a speed of about 14 km/s (8.7 mi/s), entered the atmosphere, it began to break apart, and the fragments fell together. At an altitude of about 5.6 km (3.5 mi), the largest mass apparently broke up in a violent explosion called an air burst.


I found an original film documenting the meteor on YouTube. It is in Russian with English subtitles. Endearing period piece, especially the musical soundtrack which seems inspired by Walt Disney and the hand-held camera.



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 Post subject: Re: Meteorite from the Sikote Alin fall in Russia in 1947
PostPosted: Mon May 09, 2016 10:16 pm 
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Perhaps not the most directly relevant, but one must be careful with meteorites set in pendants. I set one for my friend to give to his girlfriend (Campo del Cielo, not Sikote Alin, but very similar)--it worked great for them until they visited Boston, where it began to rust after only a few days in the salty air. Polished right off but he wasn't exactly rushing back to me to get another piece of jewelry after that.


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 Post subject: Re: Meteorite from the Sikote Alin fall in Russia in 1947
PostPosted: Mon May 09, 2016 10:58 pm 
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:shock: Oh. San Francisco is definitely a seaside climate, salty and damp.....Marin, not so much. I'll let you know.


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 Post subject: Re: Meteorite from the Sikote Alin fall in Russia in 1947
PostPosted: Wed May 18, 2016 3:20 pm 
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If iron meteorite is fresh fall, i would have frankly used vegetable oil or any other cooking oil to make it occasionally rust free. But don't use any sort of oil or acidic compound on chondrites and achondrites, its just my suggestion, i'm still learning :)


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 Post subject: Re: Meteorite from the Sikote Alin fall in Russia in 1947
PostPosted: Wed May 18, 2016 4:05 pm 
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I have been subsequently told that the Sikote Alin meteorites are high in nickel low in iron so they don't tend to rust. I don't know, not my area.


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 Post subject: Re: Meteorite from the Sikote Alin fall in Russia in 1947
PostPosted: Mon May 23, 2016 3:37 pm 
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Yes i agree, apart from mesosiderite any meteorite which has more metal than other minerals is probably classified as iron meteorite, but some highlanders are very similar to slags :)

I will post photos of some rocks here later.


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 Post subject: Re: Meteorite from the Sikote Alin fall in Russia in 1947
PostPosted: Sat Apr 29, 2017 10:36 am 
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Sikhote-Alin octahedrites are really nice. Also check those rough Admire pallasites:

Image

Image

However rust tends to eject olivine grains from the matrix, thus these meteorites need to be stabilized.


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 Post subject: Re: Meteorite from the Sikote Alin fall in Russia in 1947
PostPosted: Sat Apr 29, 2017 12:40 pm 
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Those specimens are absolute treasures.


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 Post subject: Re: Meteorite from the Sikote Alin fall in Russia in 1947
PostPosted: Sat Apr 29, 2017 1:58 pm 
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I love the one that looks like a sea dragon


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 Post subject: Re: Meteorite from the Sikote Alin fall in Russia in 1947
PostPosted: Sun Apr 30, 2017 10:33 am 
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Stephen Challener wrote:
Perhaps not the most directly relevant, but one must be careful with meteorites set in pendants. I set one for my friend to give to his girlfriend (Campo del Cielo, not Sikote Alin, but very similar)--it worked great for them until they visited Boston, where it began to rust after only a few days in the salty air. Polished right off but he wasn't exactly rushing back to me to get another piece of jewelry after that.


Stephen,

I was in a rock shop in NH a couple of months ago and bought a small (20 grams) Campo del Cielo: The owner told me to be careful with it, as they are very much prone to rusting, more so than most other types of meteorites.
I'm sure it has to do with the chemical composition.
As far as Nickel bearing meteorites go, remember that Nickel does NOT rust, and it is one of the main constituents (with Chromium) of Stainless steel.
One of the very common types of stainless is an 18-8 alloy, with 18% Chromium, and 8% Nickel.
So, I would not be surprised that high Nickel meteorites are more resistant to rusting.
And that is a killer picture of the meteorite with Olivine! A treasure indeed...
Thank you to everyone for sharing pictures and information!

-Tom


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