Jewish participation in trade on the Silk Road seems to be all but guaranteed Lena Cansdale's article, "Jews on the Silk Road." I found particularly interesting the mention of their status as "dhimmis" in Persia, as it would have very easily have facilitated their ability to trade with wide-ranging groups of people. Not only would they have friendly relations with the Christians in the West, but they could also travel unharmed (ignoring the harsh weather conditions) through Islam-dominated regions, often establishing communities along the way.
http://www.iajgs.org/cemetery/afghanistan/ghur.html
The discovery of a Jewish cemetery in Afghanistan reminded me a lot of the presence of Nestorian Christianity in China. The presence of Christian symbols alongside Chinese script seems just as mismatched as the "Judeo-Persian" inscriptions on tombstones found in Afghanistan. The Christians' and the Jews' statuses as second-class (but also protected) citizens likely allowed for their mostly unobstructed journeys to the Far East, which left behind these religious and cultural oddities.
