To all treasure hunters... You may be throwing away meteorites! Don't throw away hot rocks until you check them and verify they are not meteorites.
Those of you who hunt gold nuggets and relics in the deserts of the southwest, Alaska, or anywhere for that matter have run across pesky hot rocks. Highly mineralized rocks that make your metal detector sound off and make you think you found something good, even if only for a moment. Nuggetshooters, metal detectorists, and relic hunters have all kicked, thrown, or tossed hot rocks in the bushes at one time or another. It's something that's jut an everyday annoyance to most hunters.
Meteorite hunters on the other hand, check the bushes and old dig holes for hot rocks which might be a meteorite! (by the way; shame on anyone who doesn't fill their dig holes!)
Many meteorites have been found next to old dig holes, in bushes, or in rock cairns and were obviously put there by a human. That human was most probably a nuggetshooter or relic hunter.
Stone Meteorites may not look like anything special. But they will make your detector sound off and many a hunter has been fooled into thinking it was nothing more than a hot rock. Gold detectors are particularly useful in finding meteorites. Their extreme sensitivity that makes them good for gold nugget hunting, also makes it very sensitive to the iron content in meteorites. Simply don't use discrimination. Stone meteorites contain a high percentage of nickel iron, higher than any other Earth rock. This sets off the detector and will sound similar to a hot rock. (Note: Iron meteorites are a bit more obvious and can easily be identified as an uncommon rock in the field)
It's important to be able to identify a meteorite while in the field. There are a number of field ID methods and certain characteristics of meteorites you should be on the lookout for.
Magnetic: Because most meteorites have iron in them, this makes them magnetic.
Heavy: Meteorites tend to be heavier than most Earth rocks both due to density and iron content.
Fusion Crust: Meteorites enter our atmosphere at thousands of miles per hour on a fiery course towards Earth's surface. This causes the meteorite to have a burned look. It's actually a glassy like thin melt crust on the outside of the stone, and will look like a charcoal briquette on freshly fallen meteorites. Older meteorites which have been weathering for hundreds or thousands of years could have residual fusion crust and a reddish or oxidized desert varnish exterior.
Regmaglypts: Meteorites, both iron and stone, can have regmaglypts, or "thumbprints". These are depressions, scoops, and ridges on the exterior of the stone caused by ablation as the meteoroid enters our atmosphere. Material melts away from the meteorite and "burns off" leaving these thumbprinted like surface.
Streak Test: The streak test is used to rule out magnetite or hematite which will leave a streak on the non-glazed side of a bathroom tile. Most hunters I know don't rely on this method, but have used it to identify some meteorwrongs. The logic is that meteorites don't leave streaks, but this is sometimes unreliable because meteorites contain iron, and will oxidize. This oxidation will leave a "rusty" streak on the tile.
Windowing: Meteorite hunters will typically carry a piece of very course grit sand paper or a small pocket file in the event they find a meteorite. This aids in identifying possible meteorites when you sand or file a small "window" on an inconspicuous surface of the stone, exposing the interior. You're looking for two things. Chondrules, and iron. 90% of stone meteorites are classified as chondrites. Chondrites are named for their chondrules (little spherules a few milimeters in diameter, with the matrix of the stone). Iron should also be visible as metal bits or flecks inside the stone too.
Visual Examination & ID: Carry with you a 10X jewelers loupe. For most treasure hunters this is a common tool in their tool bag. Use the loupe to look for chondrules and the iron flecks within the stone. Use it to examine the exterior of the stone looking for signs of glassy like fusion crust. Also look for olivine crystals. Many meteorites may have visible greenish colored olivine crystals within the matrix of the stone.
If you have found a rock that meets all of the above criteria. you MIGHT have a meteorite!
Meteorites are rare, more rare in fact than gold or diamonds. But they are found in every state of the USA, and on every continent on our planet. As of this writing some 50,000 plus meteorites have been found, classified and cataloged througout the world. There may be one in your own backyard!
Take a look at some of the meteorite photos below which exhibit some of the features listed above.
If you have a question or think your "hot rock" might be a meteorite. Feel free to post it here!
Enjoy...
Eric
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Regards, Eric Wichman Meteorite Hunting & Collecting Magazine You are not allowed to view links. Please Register or Login
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