Easy Inlay's jewelry-grade cultured opals contain the fire typically seen in rare, natural opals. They are optically and physically identical to those found in nature, but their color will never fade. Large 2-3mm grains with brilliant facets of noticeable fire fill larger voids, and they are easy to crush to fill smaller spaces, too. Krakatoa FINE grains are 2mm, 30 mesh. 2 grams fill 30" by 1/8" deep by 1/8" wide.