Cordonnet crochet cotton size 30
Steel crochet hook US size 11 (1.0mm) or size for gauge.

First 2 rounds of motif = 1.25” in diameter measured across picots.

Advanced. 3 tr cluster. No additional border. Diamond shape.

25 motifs joined at picots in final round

Pattern 4, pg 15 of Magic Crochet.
Shown on cover of Crochet Monthly.