In US terms: Size 10 hook, 400 yards of size 20 thread

This is a Delta Crochet doily, DC810.

To crochet the doily you need to know some basic Delta Crochet Techniques. A tutorial with all the stitches used is posted at Hass Design, Another way to learn the techniques is to take the Star Jasmine Crochet-Along.

This doily uses chains, slip stitches, tr’s, 2-tr puffs, picots and joined tr’s.