about 1/4 Inch across and 1/2 Inch long or approximately 1cmx2cm

The way opal gets its color is the manor in which the molecules (silica oxide sepheres) that its made are stacked on each other, different shapes create different different colors based off of the light that refracts through the molecules.

Lab created opals are grown in a laboratory using pure silica or a polymer-resin, instead of water, to fill the gaps between the silica oxide spheres.

The process takes from 1 to 2 years and results in a similar structural and chemical makeup to natural opals but with increased stability and durability. Creating Opals in a lab is still not easy and is an art in it of its self.