Store › A 6mm opal bead necklace in a choice of blue or white. Image 1 of 7 Image 2 of 7 Image 3 of 7 Image 4 of 7 Image 5 of 7 Image 6 of 7 Image 7 of 7 A 6mm opal bead necklace in a choice of blue or white. £70.00 I really can't decide which colour I like more, the blue has lovely hints of green and the white has a beautiful array of colours.The beads are 6mm and on a 1mm sterling silver trace chain which can be either 16" or 18". Add To Cart Added! I really can't decide which colour I like more, the blue has lovely hints of green and the white has a beautiful array of colours.The beads are 6mm and on a 1mm sterling silver trace chain which can be either 16" or 18".