Does it have a rusty brown, to black fusion crust? When meteorites are relatively fresh, they often have a thin black crust of melted rock or in the case of iron meteorites a bluish black crust.Notice the tan-brown surface with dark brown patches of fusion crust. Macy, NM L-6 (weathered stone), 368 grams. This meteorite has a thick oxide coating that flakes away. Toluca, Mexico, iron meteorite, 658 grams. On stone meteorites this will look like a dark brown varnish and on solid iron-nickel meteorites this is often a thick crust that flakes away. The iron and iron grains found in them rust with exposure to the earth's environment, and will coat the rock with a layer of oxides. Is it rusty brown, or black? Most meteorites are rusty brown if they have been on the ground for an appreciable amount of time.In this specimen cut lenghtwise the solid malleable metal interior is revealed.
Notice the numerous iron-nickel inclusions scattered throughout a stony matrix in a nearly 50-50 mix.Ĭanyon Diablo, Arizona, ("Meteor Crater")iron meteorite, 245 g. Lamont, Kansas Mesosiderite, (stony-iron)70.6 grams. Notice the white malleable metal grains in this expertly cut specimen. This 96 gram full slice is from a stone that was picked up shortly after a bright meteor was sighted. And because malleable iron-nickel is extremely rare on earth, but common in most meteorites, it is one of the distinguishing characteristics in determining whether the rock in question is meteoric or not.Ĭampos Sales, Brazil L-5,(stone), Fell Jan 31, 1991. On the other hand, stone meteorites will pulverize and within the brittle stony matrix are malleable metal grains that flatten rather than crush. Because iron meteorites are comprised almost entirely of malleable metal, when struck with a hammer they will dent or bend rather than break. And if the object in question is solid iron-nickel then it will look exactly like a rusty lump or chunk of steel that is silvery inside. Often metal grains appear on broken surfaces of stone meteorites as rust spots, especially if it is weathered. To see the metal or metal grains within a meteorite you must grind a small window on the specimen. The rest, less than 2% are the stony irons having an almost 50-50 mixture of stone and malleable iron-nickel. 93% of all meteorites seen to fall are stones, and only about 5% are solid nickel-irons. This amount ranges from a few percent to 100%. This is not only because of the types of minerals found in them but because almost all of them have varying amounts of malleable iron-nickel grains.
Is it heavy as compared to most rocks? Meteorites have a high specific gravity and tend to be denser than most earth rocks.SO you think that you may have found a meteorite?ĭoes your suspected space rock fit the following criteria? The purpose of this page is to present information that will better aid the reader to recognize meteorites. But in this task very few samples submitted turn out to be meteoric.
We invite the submission of suspected meteorite samples for identification and appraisal. For over twenty years the American Meteorite Survey has endeavored to find, catalog and distribute meteorites to institutions and collectors. Because the earth's crust is so rich in iron oxides and iron minerals, meteorite identification is a daunting task for the layman, and even the professional geologist.