I finally got the samples in the mail!  I couldn´t find the volunteer registration form, though, so I thought I would just tell you where they are from now.  The grey sample is from Potosí, Bolivia.  It is from the Cerro Rico, which was one of the richest mines in the world during the Spanish colonial period.  The main mineral mined then was silver, almost pure. This mine basically underwrote the Spanish Empire for two or three hundred years.  Tragically, the Spanish used both indigineous and African slave labour in the mines.  They forced the slaves to stay inside the mines for one year and six months time with no opportunity to leave. After that the slaves were free.  Of course many, if not most, didn´t make it.  It is estimated that 8 million people died in the mine during the Spanish Empire.  There is still mining going on, but now it is mostly for zinc.  There are also still children working in the mine and conditions are still mostly rudimentary, though while the government owned the mines they did install some ventilation in some parts of the mines.  The mountain and town are now UNESCO sites and some people would like the mining to stop to preserve the mountain, but to this day it continues.

The second (red) sample is from Inkamachay, a boulder covered in paintings that date back from 2000-1500 BC.  I have photos of this which I will upload when I get a chance, but it may take awhile as the internet connections in Bolivia are very slow and I may need to wait until I get to Argentina.  The paintings are located near Sucre (the cradle of liberty--where the war for Independence was begun).  They are also close to a portion of the Inca trail and were most likely painted by people who were passing through the area on the trail.  There is another cave with drawings in charcoal nearby, but the most important drawing in that cave was stolen in the mid-90s.  They are now protected by the local people.

Let me know if you need more information.

--Sara