Knitted lace bookmark, with crochet edging (no hook size given). Pattern is illustrated at each stage, and instructions are well-written.

From the designer’s website:

This bookmark is made by knitting the scallop shell on the lower end, picking up stitches along the sides and base of the shell and knitting upwards, back and forth across the full width for as many repeats of the shell pattern as desired. One final repeat of the shells is worked, knitting another scallop shell in the center instead of the cowries and eyelet triangle that are part of the main pattern.