craftgrrl | mysterious afghan stitch?

hi, long-time lurker, first-time poster.

i recently got some stuff out of storage that had been in a flood. much of it was totally ruined, but all replacable things, amazingly. the irreplacable things, such as this afghan, survived. my great-grammy henrietta made it for my mom back in the 60s, and a few years ago my mom passed it onto me.

i was hoping the crafty people here might be able to give me a clue about what sort of stitch she used. i am a beginning knitter/crocheter and i can only do the most basic things. my grammy was a master, and i would really like to be able to duplicate the stitch in this afghan. it has lasted many, many years and gone through a lot of wear and tear, and is still in amazing condition. i'm sure it will still be around when my kids are old enough to have heirlooms passed to them.

i took some pictures of it with my camera-phone. i hope they're detailed enough to give you an idea of what the stripes and edging look like.