Meteor???

[gaznazdiak]

I found a piece of black rock the other day that looks to resemble what I imagine a piece of meteorite might look like. One side has an even layer of vitrification, about 3mm thick and a deeper black, and the opposite side looks to have melted and flowed and shows small striations reminiscent of those on steel that has been cut with a plasma torch.
Can anyone suggest how I might find out?:help::confused2::thanx:

[jjjnettie]

http://www.meteorites.com.au/found.html
Hope this helps you.

[Matt Wastell]

Hey Mick,

Let us know how you go!!!!!!

From your initial reports it sound plausible - but I know very little.

Is a magnet attracted to it?

[tlgerdes]

I think we should rename you Nettiepedia.:lol:

[gaznazdiak]

Thanks to Matt and jjjnettie for your response to my query. The rock in question isn't magnetic and having looked at the meteor site you suggested, it doesn't seem to fit any of the categories listed. The area in which I found it is all granite, but this is the most 'un-granite-like' rock you're likely to find, in fact it looks like jet black quartz. I will send the details and some close-ups to the meteor site and let you know the results.

[adman]

Now, I know very little (ok - nothing...) about meteorites - but that looks like what I think a meteorite should look like!

[renormalised]

Do you have a piece of white, ceramic tile?? If you do, rub the rock on the tile and see what colour the streak is. If it's reddish brown, it'll be hematite (a hematite concretion). If it's dark grey-brown to black, it'll be magnetite (but since it's not magnetic, that rules this out). If it streaks either yellow or a brownish yellow colour, it's either limonite or goerthite. It's most likely, seeing it was found in granitic rocks/soils, a weathering product known as a gossan. Was there more of this rock lying about the place??. If so, you may have stumbled across a mineral deposit...these iron rich gossans usually form as weathering caps to mineral deposits anywhere there is a lot of iron in the mineralisation, especially in granites and iron rich metamorphic rocks.

[jjjnettie]

The underside of a normal dinner plate has a raised rim that is usually unglazed. You can score the rock across that to see if it leaves a mark. :thumbsup:

[renormalised]

That'll work, but SWMBO mightn't be too happy to have her plates all marked up with rock grit!!!:):P:P

[AstralTraveller]

Mick,

If you photograph something like this it is normal to include a scale. If you can't get a 'proper' scale bar use a ruler, coin or something everyone knows the size of. In the field geologists, sedimentologists etc often use their G-pick, shovel or camera lens cap. (I've also heard of less appropriate scale bars but lets not go there.)

At the moment I don't know whether the rock is 0.1mm across or 1mm, 10mm, 10cm or half a football field. :D

There are a few ways such an 'erratic' may have go on to the granite. If there is higher ground nearby it may have washed down, and that could have happened so long ago that it is no longer near a stream. The surface in your first photo looks pretty much like an effect caused by flowing water that is cavitating (I've forgotten the term). Otherwise, was the rock near a road or other places where people have moved things around? That is a trick for young players.

Carl suggested you check the streak. Density and hardness are other characteristics you can easily check.

[renormalised]

Yeah, Geologists....them's deviant people:):P:P

I know:):P

[gaznazdiak]

At the very top of the first photo you can just see the edge of the steel ruler I used to show the scale, I just cropped a bit too much off the photo to bring the size down. The markings visible on the ruler are 1 mm.
Someone suggested that as the face in the first photo has so obviously been melted, it might be volcanic, which of course still begs the question: How did it end up buried in my paddock, over 1/2 km from the nearest road?
I'm also going to see if Goulburn has any professional 'rock lickers' who might be able to help.

[jjjnettie]

:D I do believe you have a nice piece of volcanic glass.