What is Tiger Spar and What is it doing in my Rosary? (UPDATE)

There's a new Rosary in the shop, with a little known stone for the Our Fathers--Tiger Spar.

The term, tiger spar, seems to be common among Asian merchants; I have not seen it in vendors on this side of the world.  I spoke with a friend who had taken a sample to her gemologist, and apparently this is a feldspar: To be more precise, the dark green is serpentine. There are bands of chautoyant material--that is, it looks different from different angles and has a certain amount of 'flash.'  In the case of these beads, the flash is brilliant teal green against a background of forest green. You can barely pick it out in the top pic, but the half hidden bead in the bottom also shows a band of it. These bands are a crystallized amazonite, so strictly speaking, tiger spar is a combination of two different minerals. I thought it was an overdyed stone, as the teal was so brilliant and intense, but apparently it is NOT--that's the property of the stone! It also comes in a form with serpentine and pink bands...would love to see that.  So Many Thanks to Kate for the info!
It's been prayed to check to make sure all crimps are silky smooth, and it's ready to go to a forever home now--check out the shop for this and more...

All for now,
j