In the second paragraph it says: "For instance, one emerald mine established in 1981 in Santa Terezinha, Brazil, produced a peak of 25 tons of rough stones valued at $9 million in 1988; the same tonnage of stones mined in 2000 sold for only $898,000." If I took that sentence seriously, I would have to infer that the price dropped by an order of magnitude, presumably because other productive mines had been opened. But the preceding sentences says the contrary: "Thus high-quality gems can be mined out much faster than they are produced, essentially making them a finite resource." "The same tonnage" must be wrong. Please clarify.
posted by Joseph Fineman
February 20, 2012
About once a month at Sigma Xi headquarters, we liven up the lunch hour with an American Scientist Pizza Lunch talk. In these informal lectures, scientists describe new research to nonscientists. The series is light on jargon but heavy on solid science. Each Pizza Lunch offers an in-depth look at its subject, whether it's bedbugs or the smart grid. Click below to read about and download these talks -- and to subscribe!
JSTOR, the online academic archive, now contains complete back issues of American Scientist from its inception in 1913 (as Sigma Xi Quarterly) through 2005.
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View the full collection here.