This scarf uses the Lacy Diamonds stitch.

Any of the lovely lace patterns in this section of the book can be used to Any of the lovely lace patterns in this section can be used to create lightweight scarves or shawls. For this example, I chose a luxurious merino blend sock yarn which drapes so beautifully, and I crocheted it in the lacy diamonds pattern …. A simple shell trim finishes the ends in style.

Hubert, Margaret (2014-07-01). The Complete Photo Guide to Crochet, 2nd Edition

Note: Zen and the Art of Stash Diving Scarf uses this same stitch. The edging and width of the scarf look to be different between the two patterns.