Is this a tectite

[rally]

Just wondering what the collective thinks this is.

A friend of mine had it sitting on his cupboard with a mixture of odd rocks. He found it in his youth somewhere in Central Australia.

It is definitely not as dense as ironstone or a meteorite, it weighs 72g.
I couldn't find a measuring cylinder tonight to work out its volume and actual density.
Its shape is almost two perfect 29mm diameter spheres joined together, with a bit of a lump on one side.

Surface is generally smooth to touch.

I thought it might be a tectite but haven't seen them this shape before.

All serious comments welcome.

Rally

[Jen]

a what it looks like doggy do-do

[jjjnettie (Jeanette)]

I've no idea what it is, interesting specimen though.

[[1ponders] (Paul)]

The texture looks about right but viewing it through a red gel screen doesn't help Hang on while I lose my night vision.

Hmmmm...looks the wrong colour... my tectites are black.

[rally]

Thanks for the serious comments.

Colour is a dark rusty brown, looks very much like an iron nodule, and could possibly be a mineral of some sort.
Doesn't seem heavy enough for iron though.

Polished surface finish could be from repeated handling, but might be original - I dont know.

Trevor might know ?

[[1ponders] (Paul)]

It looks a little bit like what is called a Boji Stone, I have oe that looks similar in colour and texture, but shaped like a 20mm long bean seed, but I dont know if Boji are found in Aus

[OneOfOne (Trevor)]

Could be a tektite...maybe two molten balls of impact material have contacted with each other before they landed back on the ground? Do you know if it was found in an impact area, although some impacts can throw material a couple of hundred kilometres.

You could perhaps send an email and couple of pictures to Norbert Kammel at:

meteorites@rocksonfire.com

They are a local meteorite distributor in Melbourne and may offer a good educated opinion.

[[1ponders] (Paul)]

Definitely looks like a boji stone. I just checked mine and it could be a twin to yours in texture and colour. I'll take a shot of it when I get home this evening and post it to compare.

[rally]

I should also mention that it is non magnetic

[Garyh]

Looks like a Tektite or if it is a Australian Tektite it`s a Australite. Tektites are made up of a reconstituted glass with similar characteristics to the rock where the impact happened. Very similar to say obsidian, volcanic glass. If you hold it up to a very bright light can you see any light through a very thin edge? That bumpy part almost looks like it is part of a flange also. I say 90% chance it is one.
Very unusual shape but! Maybe on it`s way to becoming a dumbbell shape but impacted before this could happen or was spinning at a slower velocity?
Me and my wife have both found Tektites and once you have seen one lying on the ground it is quiet unmistakable!
cheers

[Baddad (Marty)]

Tektite/Australite?

A source of info: http://www.meteorite.com/tektites/index.htm

I think you may have a tektite. Check out the sale prices of tektites as well.

[Baddad (Marty)]

Last month I had the fortune to visit Arizona. The Meteor Crater in particular.
It was awesome. 700ft deep, 4000 ft across. The meteor struck this flat Arizona desert 50,000 yrs ago. Travelling 11 miles/sec. and measuring about 150 ft diam.

It shifted, in seconds, 196million tons of sandstone and limestone. Drilling expeditions to locate the core revealed that the molten core was scattered with blown out debri.
Iron and sand mixed rocks have been found miles from the site. They sell pieces at the site, They are not tektites as defined but a mixture of about 95% iron and once molten sand grains etc.

This meteor was only small to what is still lurking in our solar system.

[Roger Davis]

http://www.australites.com/australi2.htm

One in here similar to yours.

If the energy of the impact was dissipated then there would not have been enough energy for the balls to separate. There are many dumbell shapes and individual ones. So yours could be a conjoined tektite.

[AstroJunk (Jonathan)]

Without doubt an ironstone concretion.

http://images.google.com.au/images?s...-8&sa=N&tab=wi

You would have to slice it before discounting it due to weight - they can be hollow. There is a simple test if you have a spare ceramic (bathroom) tile handy. Scrape the object across the back surface and it it is ironstone it will leave a dark red to black streak. If it is glass, then nothing.

[Ric]

Hi Rally, from my Geology days in the Kimberleys and from your pictures I'd say they are Ironstone concretions.

I have seen similar occurances in sedimentary beds in that region.

[rally]

Thanks for all the suggestions.

I'll try and do a tile test tomorrow and report back what happens.

Rally

[rally]

Tile Test results :
Rubbing the pointy lump across the unglazed side (back) of a wall tile, resulted in a very faint dark reddish/brown line that wiped off easily

I am not convinced that test is really all that conclusive, but I am leaning more toward it being a mineral.
It certainly looks more like an iron nodule than any tectite photo I have seen.

Rally

[AstroJunk (Jonathan)]

Originally Posted by rally

Tile Test results :
Rubbing the pointy lump across the unglazed side (back) of a wall tile, resulted in a very faint dark reddish/brown line that wiped off easily

I am not convinced that test is really all that conclusive, but I am leaning more toward it being a mineral.
It certainly looks more like an iron nodule than any tectite photo I have seen.

Rally

Take it from a geologist (ex), you don't get much more conclusive than that

[rally]

OK Jonathan.

Ironstone nodule it is !

I shall return it to my friends collection.

It was an interesting journey !

Thanks to all who contributed

Rally

[Baddad (Marty)]

What a shame. I would have liked it to be something kind of spectacular. Such as a tektite. However we all learned something there. I had forgotten about the streak test.

Cheers Marty