Texas Meteorite Hunters

[CMD]

There is an ongoing surface hunt in Edgewood, Texas and vicinity for space rocks at the moment. Not unlike surface hunting artifacts. Know what they look like through experience and walk, walk, walk. They're out there. Sometimes they don't turn up for years, sometimes these "right after the fall" hunts pay off. Some nice meteorites from Texas. Maybe some to be found around Edgewood for you Texas folks

http://www.kens5.com/news/Texas-meteor-hunters-zero-in-on-intergalactic-treasure-138780909.html

[greywolf22]

The Big Bend area is a good place to look also. They are there like you say you just got to walk for them. I have found only one and was not sure until I picked it up. It was heavy for its size.
Jack

[rokhedred]

How do you tell meteorite from iron ore? I have a few things that stick to magnets, but not sure what I have.

[painshill]

rokhedred wrote:

How do you tell meteorite from iron ore? I have a few things that stick to magnets, but not sure what I have.

  There are a number of characteristic features of meteorites which depend a little on whether we are talking iron (nickel-iron), stone (chondrite or achondrite) or stony iron (pallasite or mesosiderite). These features can be confirmatory if present, but the absence of these features doesn’t rule out meteorite:
Fusion crust - rich (normally matt black) surface rind that's not more than a couple of millimetres thick. Very obvious when freshly fallen. Less so if rusted.
Regmaglypts – small depressions that look like a thumbprint made in wet clay.
Flight-orientation – most meteorites are rounded but will frequently approximate to a cube, or have one face that appears to be flattened. A kind of “shield-shaped” profile would be a classic shape.
Flow lines – these look like small “rivulets” of molten material that have re-solidified. If a flattened area is present, these will seem to run away from that area, but will all run in the same general direction.
Roll-over lips – these will normally be around the edge of the flattened area, if present. They look like the thin edge has been folded back on itself, away from the flatter area.
Cracks – cracking will frequently be present from detonation in flight, impact or heat-shrinkage, especially for stony meteorites.
Iron meteorites are extremely dense. If you know how to check the density by water displacement then an iron meteorite will be around 8 grams per cubic centimetre (66 ounces per cup). Even very dense Earth rocks like hematite won’t normally get much beyond 5 g/cc (42oz/cup). You might be able to make a crude judgment in your hand. If you can find a comparison rock that’s about the same size (a bit of basalt or granite maybe) then your find should feel at least twice as heavy.
Try a streak-test on the back of an unglazed ceramic tile. A non-rusted portion of an iron meteorite should not leave a streak. If it leaves a black/grey streak it’s almost certainly a lump of magnetite (normally strongly magnetic). If it leaves a red/brown streak, it’s almost certainly a lump of hematite (normally only weakly magnetic at best). These two minerals often occur as a mixture, so intermediate results are possible eg dirty streak and moderately magnetic.
If there are visible crystals embedded in it then it’s definitely not a meteorite unless those crystals are yellow or greenish-yellow and have no obvious crystal shape.
The odds are very much stacked against you because there are so many other terrestrial rocks which look like meteorites. We call them meteorwrongs.
The most definitive confirmatory test is laboratory analysis for nickel content. It’s possible to do a semi-quantitative test yourself, but it’s neither cheap nor simple and may be prone to false positives.
Painshill

[painshill]

greywolf22 wrote:

The Big Bend area is a good place to look also. They are there like you say you just got to walk for them. I have found only one and was not sure until I picked it up. It was heavy for its size.
Jack

  Jack
“Heavy for its size” is not a good indicator on its own unless the density approaches the value I gave in the above post.
It used to be the case that testing and classification required a 30g sample (or 10% of the mass), but things have improved. NEMS offers a 10-14 day testing service for $15 and they only need a representative piece about the size of your finger nail.

http://www.meteorlab.com/METEORLAB2001dev/identification.htm

Once you have positive identification and a classification you can apply for a formal name via the International Meteoritical Society and get your name in the database as the main mass holder (cool!). B)  Unfortunately, they won’t name a meteorite after you.  The name is normally the nearest place with a post office or a prominent geological feature if found in a remote area.
Incidentally, if you ever find a meteorite that’s freshly fallen, get it dry as quickly as possible. A low oven (not a microwave) for a few hours will do it, and/or a sealed container with some silica gel not in contact with the specimen.
There’s one other thing you should always do. Throw it at your foot as hard as you can and try to make a big bruise. Meteorites that have hit something will fetch a much higher price with collectors (we normally call them “hammers”), especially if they have hit a person. Don’t mention I told you that. :whistle:
Painshill

[rokhedred]

Thank you for all this info! I don't think I will be able to slice a piece off for evaluation, though. And I really don't want to bruise MY foot. I think I will throw it at someone else for the "hammer" notation!!! Thank you once again for the info!