This is Snowflake #37 in the book of 100 Snowflakes. Instructions are on Page 63. It is pictured on page 28 in the showcase.

“Nieve penitente (also called penitent ice) is a pillar of compacted snow or ice, found most often in the Chilean Andes.”

Finished diameter: 2 5/8 in (67 mm)
Thread required: 5 yd (4.6 m)

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