An Article In Meteorite-Times Magazine
by Robert Verish
Another "Sulfide slag" source found - it's FERRO-MANGANESE
UPDATED (2009-07-07): with new links and revised terminology
HERE is a link to my latest Bob Findings (July 2009) article about an Update on "Slag Meteor-wrongs"
Perhaps it's just me, but there seems to be more mention of meteor-wrongs, lately. Perhaps there are more people actively searching for meteorites and, as a result, more meteor-wrongs are being found. But, I've also noticed that, when there is a mention of real meteorites (or fireballs) in the media, there always seems to be a rash of meteor-wrong findings that follows soon afterwards. Many times it's the mention of meteorites in the media that prompts the decendants of "meteorite finders" to fetch "grandpa's doorstop" out from the barn to "get it looked at". Although this scenario is actually how some meteorites have been brought to the attention of researchers, it is more often the case that the "family heirloom" is found to be nothing more than a disappointing meteor-wrong.
In the process of giving lectures to clubs and presenting displays of "real" meteorites (and even meteor-wrongs) at their meetings and shows, I am very often approached by people who have "found a meteorite". What this means is that I get to examine a lot of "meteor-wrongs". I get to see a lot of the typical hematite nodules and magnetite "irons", but there was this one type of meteor-wrong that I was consistanly being shown by a variety of people. It wasn't that great of a meteor-wrong because it wasn't attracted to a magnet, and it wasn't made of metal, but it was ALWAYS black, and heavy, and every person that showed their specimen to me were convinced that "it had to be made of metal". But, like I said, it wasn't metal. Granted, the interior had a metallic luster, but it wasn't "made of metal". When I would tell the finder that their "iron" was a man-made stone called "slag", they would always reply, "But it isn't glassy and it doesn't have any bubbles!"
And that's why it was necessary for me to coin the phrase, "Sulfide Slag".
But, although I was encountering this atypical meteor-wrong every more frequently, from a variety of people, I never could get a consistent story that would give me a clue as to a possible common origin. The consensus was that it had to be a by-product of a smeltering process, most likely in an iron furnace.
Opening of Science of Rocks Show - - - My meteorite display at the Show
Then, last month, at one of those "Gem Shows" where I had my meteorites on display, a person handed me "a meteorite" that his son had found while walking to school. Well, I immediately recognized the hefty black rock as being, not only a meteor-wrong, but as being another specimen of that "sulfide slag". I said to this person, "This rock isn't attracted to a magnet, is it?" The person sheepishly admitted that, "No, it doesn't attract a magnet, and I read somewhere that most meteorites are magnetic, so I guess that doesn't bode well for this being a meteorite. Does it?" I didn't answer his rhetorical question, but instead asked another question, " Was this found near some railroad tracks?"
My question seemed to surprise him, and he answered, "Yes! How did you know that?"
I then proceeded to tell him my story about "sulfide slag" and my search for its (presumed) common source.
As-found sulfide slag specimens - - - and after cleaning away the coating of clay and MnO2 powder.
All of this got me to wondering:
1) Just how common is this type of sulfide-rich slag?
and, since I knew that slag is used as ballast on the track-beds for railways,
2) Just how far would I have to walk along a railway track-bed before I would find my own piece of "sulfide slag"?
Since most of the railway track-beds that I was familiar with had used slag for track-ballast, I just picked a section of track that was near to my home, but was part of the main line that went up-state. I chose a 2 mile section that is used by passenger trains. But, as soon as I started walking, I discovered that the ballast used was mostly composed of natural rock. It seemed that for every 1/10th of a mile only one truckload of slag had been dumped and mixed into the track-ballast. Much less slag was being utilized than I had expected. And nearly all of that slag was of the light-colored, vesicular variety.
After walking a few tenths of a mile, finally a small piece of "sulfilde slag" was recovered. And when one piece was found, sometimes there would be a second or third fragment, as well, but never anymore than a few pieces at a time. Eventually, after walking less than 1.5 miles, I had already recovered 25 pieces of sulfide-rich, black powder-covered rock. One of the 25 pieces actually contained some iron metal, and was a meteor-wrong that closely imitated a stony-iron. The other 24 pieces were all the same, having a brassy, but granular to crystaline interior, somewhat akin to massive arsenopyrite. Cut surfaces would quickly tarnish in a matter of days if left in an outdoor environment. The exterior of each piece was a rind of decomposed sulfides forming a black powdery crust, much akin to manganese dioxide.
Tarnish developes on unprotected cut surface (right-side, left-side was protected) after just a couple weeks of exposure outdoors. The similarity of this man-made mineral to naturally occuring arsenopyrite is more than just a coincidence. [See in the "References: ", below, for the Slag piles contamination report.]
It didn't take too much detective work to track down the source of the slag used by the railway in their track-ballast. Nearly all of this slag comes from two huge slag heaps in Fontana (California) and was purposely dumped there by the Kaiser Steel Co.
[See the "References: ", below, for the Fontana Steel Mill.]
The black, sulfide-rich rock, which is here termed, "sulfide slag" [but a better term would be "ferro-manganese"], originated from a slag-heap at the former Kaiser Steel Mill in Fontana, California. This particular kind of slag is not produced (here in this country) in "steel furnaces", but was formed in the older "iron blast furnaces".
Bob's Findings - article titled, Update on "Slag Meteor-wrongs", in Meteorite-Times.com - July 2009.
|FERRO MANGANESE The interior "looks like" a natural sulfide mineral with a highly specular, metallic luster. But it is not a metal. It is actually a rock. It is composed of minerals termed, "Fe-Mn silicides"...|
My previous articles can be found *HERE*
For for more information, please contact me by email: