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Meteorite or Meteorwrong

Slag

 

Many of the meteorwrongs sent to us are pieces of slag. Slag usually refers to a glassy by-product of smelting ores to retrieve the metal. I use the term here to also include any man-made, rock-like by-product of heating things to high temperature. Thus, clinkers are a form of slag. Slags catch people attention because of their morphology. Many slags contain metal from inefficient separation of metal from the ore and, thus, will attract a magnet. Two other common characteristics of most slags are glassy (vitreous) surfaces and the presence of vesicles (gas bubbles). Many slags have very rough exteriors, unlike any stony meteorite. Many show flow features in the glass. Some even have flat surfaces from having solidified in a contained space. Slags are sometimes used in road construction and as landscaping gravel, so they’re more common than one might think.

I have not personally examined all the examples pictured here, but I suspect that most are slags. Some might be fulgurites - lithified soil and vaporized organic matter produced as a result of a lightning strike. Some might be products of electric discharges when high-voltage power lines fall to the ground. A few might actually be volcanic rocks. None of them are meteorites, however.


Glassy and vesicular; rough surface


Glassy exterior with vesicles


Glassy and vesicular

Glassy and vesicular; green color


Glassy and vesicular


Glassy and vesicular; rough surface


Even the clastic material is vesicular.


Glassy and vesicular; rough surface


Glassy and vesicular; rough surface


Glassy and vesicular; rough surface


I found these photos on a popular Internet site where one can buy and sell things. The advertisement was entitled "meteorite chondrite iron nickel 977 grams 10.7 cm land find meteor crater field" (?) and was offered at starting bid of $121. Fortunately, there were no bids. This is just a chunk of slag - vesicular glass with coarse metal. Metal is not distributed like this in stony meteorites.


Glassy and vesicular; surface flow features


Glassy and vesicular; flat surface, flow features


Surface flow features


Flat surface with flow features


Surface flow features


Glassy and vesicular; surface too rough for a meteorite


Surface too rough for a meteorite

Surface too rough for a meteorite

Surface too rough for a meteorite; contains metal

Surface flow features


Frozen rising gas bubbles



Large metal blobs and vesicles are a sure sign of slag.


Flow features on surface

 

 

Prepared by: Randy L. Korotev

Department of Earth and Planetary Sciences
Washington University in St. Louis

Please don’t contact me about the meteorite you think that
you’ve found until you read this and this.

 

e-mailkorotev@wustl.edu

Last revised: 17 April 2019