#arsenopirite

[glacialerasoul]

Postage stamps celebrating the 1st portuguese-hispanic-american congress of economic geology* issued in Portugal on September 24, 1974 by the Casa da Moeda - Portuguese Mint (later in 1972 merged with the National Printing House becoming NPH and Mint).

From left (top) to right: Beryl, Arsenopyrite, Chalcopyrite & Zinc Blend,  Wolframite;

*Took place in Madrid (Spain) from the 19th to the 23rd of September and in Lisbon (Portugal) during the 24th and 25th of September;