It's called On-line Supersocke 100, (www.online-garne.de), with a 45% cotton, 40% virgin wool, and 15% polyamid content, the yarn feels really great when knitted into socks. I used a size 2 bamboo needle for the stocking stitch portion of the sock, and a size 1 bamboo needle for the ribs.
The sock is soft, cool, and feels great...very different from the feel of the superwash wool I usually use for socks, and even feels better than the acrylic yarns I've used for socks.
On the size 2 needles it knits at 7 1/2 st/1".
I hated this yarn at first, and have found that the rib really needs to be knitted on smaller needles over the stocking stitch (something I don't usually do with socks), and once I made this minor adjustment, I've come to love this yarn.