Natural Blue Iolite Smooth Round Coin Beads Strand Length is 7 Inches & Sizes from 4mm to 5mm approx. These are 100% genuine aquamarine beads beautifully hand cut in micro facets. Aquamarine is blue color variety of Beryl Gemstone species. It usually shows the inclusions visible as the rain effect inside of gemstone. The presence of Fe (iron) in Beryls chemical composition gives it the blue color hence resulting in Blue beryl known as aquamarine.