It is a wonderful afghan. The stitch does looks much like the woven (a.k.a granite) stitch except (can you guess) it is BIGGER! LOL
Thanks for the link to the pattern, and thank you for sharing the picture.
Master of Crochet, apprentice of Knit
OTN another Black & gold Diagonal Square Potholder
OTH Baby blanket
OTH Lace doily - A vintage pattern recreating from an heirloom.