Each bead is completely unique as the application method and dichroic achieve a different result in each bead. The size is approximately 14mm round with a base of transparent Moretti Glass wrapped in 24kt gold foil and then the dichroic is applied and then the entire bead is encased in clear Murano Glass. They are exquisite. A dichroic filter or thin-film filter is a very accurate color filter used to selectively pass light of a small range of colors while reflecting other colors (from Wikipedia). Dichroic Beads are a great way to upscale your Murano Glass Jewelry.