Your beads may well be serpentine. It's a very common mineral all around the world. (It's the State Stone of California where I live, and the San Francisco Mint is situated on a hill that is composed of serpentine.)

However, something to consider is that the State Stone of Afghanistan is a mineral called "charmaksud" (spelled various ways, depending on who transliterates it, and often without an "R"). Charmaksud is a local variety of olivine—and olivine is very closely related to serpentine. In past times, Afghans valued having a strand of prayer beads made from charmaksud—it's color ranging from greenish-yellow to olive green, usually translucent to turbid. I feel fortunate to have such a prayer strand and a few additional specimens.

Any valuable green stone is very likely to be called "jade" by local people or by importers who know the stone is valuable or note-worthy. "Afghanistan jade" sound a lot like "Souchow jade," or any of the jade-substitute names that abound in Asia (particularly China), named for some region or other + "jade."

So, even though there's no local nephrite nor jadeite in Afghanistan, it shouldn't be surprising that someone would try to sell either serpentine or charmaksud as "jade."

Over the past (about) twenty years, Afghan craftsmen (some working in Pakistan) have been cranking-out stone beads for export. (We've had some dialogue about this here recently.) The green stones are largely serpentine (and to my disappointment, apparently not charmaksud). I try to buy some every year or two, because they are handsome, and generally well-made.

I hope this is helpful.

Jamey