This is Snowflake #18 in the book of 100 Snowflakes. Instructions are on Page 52. It is pictured on Page 25 in the Showcase.

“This snowflake’s dense pattern of stitching is reminiscent of ice flowers, thick and delicate clusters of frost.”

Finished diameter: 2-3/8 in. (60 mm)
Thread required: 6 yd (5.5 m)

All pattern samples in this book are made with size 10 thread and a size 5 (1.9 mm) crochet hook.