Rasdan,
I believe the Nantan has already been analyzed.
www.greatwallct.com/nantan.htm
The average Chemical composition in the Nantan meteorites are: Fe 92.35%, Ni 6.96%, belonging to IIICD type of iron meteorite based on the taxonomy of Wasson and others (1980). The following trace elements have been detected: C, Cu, Co, S, P, Cr, Ga, Ge, As, Sb, W, Re, Ir, Au, Ru, Pd, Os, Pr, and Mn. Ag, Cd, and Pb isotopes have been analyzed by Prof. Wang Daode and others (1993).
http://www.pgrgem.com/color/datasheets/pgrmold.html
You may find more info surfing the net... but it looks like this meteorite may be a poor choice due to weathering.
fearn,
I'm going out on a limb here... so correct me if I am wrong. Realgar and Orpiment are an Arsenic Sulfide. In an acidic environment, the sulfur is released and bonds to the iron creating an Iron Sulfide (the brownish black color that is difficult to reproduce). Phosphorus will react to make a Phosphorus Sulfide, which is a pale yellow in color.
Here are some interesting links
http://forums.swordforum.com/showthr...readid=4873&s=
http://www.sanztrust.org.nz/archives/knife.html
http://epswww.unm.edu/iom/Howto.htm
BMStar