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The E-Sylum: Volume 4, Number 3, January 21, 2001, Article 6


Dan Demeo writes:

"With regard to Rafael Delgado's inquiry about metals having specific gravity around 7 (6.9-7.3), there are lots of choices, some of which could be eliminated easily:

  • chromium--7.20, but too hard to strike coins
  • cast iron--7.2--but brittle, and it rusts
  • tin--7.28--a good possibility
  • zinc--7.14--another good one

There are quite a number of metals and alloys which fit the range specified. One way to determine the composition is to put the object in a scanning electron microscope (SEM) and analyze the surface using energy dispersive x-ray analysis (EDX). PCGS has had this done, so Mr. Delgado should be able to have his object (coin?) analyzed or authenticated through them. Or, he could look up local laboratories offering SEM/EDX services or x-ray fluorescence services. On the bad side, it might cost several hundred dollars for the analysis, but he will have an answer, which is always better than all the guesses in the world."

Wayne Homren, Editor

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