Getting some photos with the macro lens, a Canon EFS 35mm. Most of these pieces of opal were purchased recently at the gem show in Tucson, Arizona. They really have some nice flashy colors. At microscopic scales, precious opal is composed of silica spheres some 150 to 300 nm in diameter in a hexagonal or cubic close-packed lattice. These ordered silica spheres produce the internal colors by causing the interference and diffraction of light passing through the microstructure of the opal.
