The colors remind me of pistachios, hence the name.
Update, January, 2011: I never really liked the deep purple/lavender color that I added in the second half of this scarf when I made it in 2008. In addition, I knit it too long. Not intentionally - it was a good length until I blocked it, and at that point the scarf grew tremendously!
So I ripped out the dark purple and knit a new second half in one color (Rowan Felted Tweed in Melody), using a reversible knit/purl stitch pattern.
New length: 53 inches. Width: 6 1/2 inches.