I crocheted the blue and the red heart with cotton thread size 10 and a 2 mm crochet hook and they are about 5,5 by 5,5 cm (2,16 by 2,16 inches). You can use heavier thread and bigger hook, or thinner thread and smaller hook and you will have a bigger or smaller motif. The silver heart as well as the variegated are crocheted with metallic thread. For the earrings, I worked with two strands of the same silver metallic thread together.
You will also need a needle to weave in loose ends and a pair of scissors.