An Article In Meteorite Times Magazine
by Jim Tobin, Editor
Putorana-Maybe the Best Meteorwrong
It does not take very long as a meteorite hunter to accumulate a good collection of the rocks that we playfully refer to as “meteor-wrongs”. And after a good many years I have seen just about everything that could pose as a Maybe meteorite. Or so I thought. I was out to dinner with a friend who was visiting from another state and as we waited for the food to arrive he pulled out a little treasure and asked what I thought it was. I took the hand lens and examined it. I was a little wary that I was being set up. It had been etched on one side and I was for several moments just amazed by the slice. I said finally, “I don’t know but I would be tempted to say it could be a mesosiderite of some kind.”
He proceeded to describe the rock and where it came from and some of the work that had been done on it. The rock was terrestrial by most expert’s opinion but it had apparently been a long study to arrive at that conclusion.
Today the name is pretty familiar to most meteorite collectors. Putorana slices and stones are in many collections. But, it has established a new marker for me personally as far as meteor-wrongs go. Here are a couple pictures of the slice I later acquired for my own collection and etched. Under a microscope the metal areas have a real similar appearance to how some pallasites look when etched. The concentric bands around the edges of the metal fields with centers of a different graining are very intriguing.
Terrestrial iron bearing rocks are rare enough as to be ignored as a possibility when hunting. They are restricted to a handful of locations on the earth. I think if any of us who hunt for meteorites was to find a rock that when we ground off a corner showed bright metal and was very attracted to a magnet we would think it a meteorite first and native iron only later. Fortunately, I will not have to worry about that since I hunt nowhere near any known native iron deposits. Still, with all the discussion of non-meteorites being sold as if they are, Putorana is one even I might have been tempted to buy as a mesosiderite if I had simply been handed a rough piece by someone. I probably would have considered it a risk worth taking. And in truth native irons are priced not that differently from meteorites, they are that rare. So I might not have made a bad financial mistake, but I might have made an embarrassing error, if I had called it a meteorite prematurely.
During the years I have hunted meteorites I have dug up countless rocks that set off metal detectors and were not. I have spent precious minutes uncovering some outrageously large magnetite nodules that gave such a strong signal that my heart jumped a little convinced that it was not just another hot rock.
It is routine to sweep the detector across banded granites, or dark gneisses just to hear the detector sound off. Sometimes the metal detector will be quite for so long that I'll swing it over one just to hear it's whine. But, it is the responses that are buried and sing out loudly and sharply, and turn out to be meteor-wrongs that discourage you a little. It has not been that long since I found a small rock that really looked like a meteorite on the outside and had what I fully believed was remnant fusion crust only to have it fail the metal grain test when I ground off a corner with my diamond file. I relegated it to the category of meteor-wrong, but brought it home, only to test it better months later and determine it was truly a new meteorite location. There are many wonderful and interesting things out there to discover. Some are not meteorites but are very close, and there are others that are meteorites but require more than a quick field test.
Putorana was another warning to me to be careful and deliberate when looking at suspect finds, and when deciding what criteria to use in determining what I’ll call meteorite and meteor-wrong.