This is a beautiful strand of faceted Ethiopian opal beads with sterling silver beads and clasp. This strand displays predominantly light yellow-green colors with minor amounts of blue, violet and even some red. The 3rd photo of this item probably most accurately shows the colors you will see in this strand.
Opal is particularly hard to photograph as the color it displays is not actually contained in the stone itself but a function of the light that is diffracted as it passes thru the stone. The play of color that we see is a function of structure of the material and will vary depending upon the type of light it is exposed to as well as the angle from which it is viewed.
The rondelle beads in this strand range from approx. 8 mm down to 4 mm. It is strung on a high-strength material called Spectra. It is 10-15 times stronger than steel yet flexible and light weight. This material allows your necklace to move and feel like it was strung on silk but it is much stronger and very abrasion resistant so it will most likely never have to be re-strung.
Learn more about Opal at this link.