Differences in the nature of the synthetic hybrid opal and natural opal
Natural opal has a regularly arranged structure of uniform silica particles which is the size about several hundred nm. Particles of this size also referred to as colloidal particles, in a state where particles are regularly arranged, play of color effect appears due to a phenomenon of light diffracion having a wavelength corresponding by its regularity.
While the typical crystal is a state in which atoms are regularly arranged, a state in which the colloidal particles are regularly arranged is referred to as a colloidal crystal. And because of that, opal is a natural colloidal crystals in a sense.
Play of color effect, a characteristic nature of opal is a phenomenon in which the wavelength of the light is changed by changing angles, in accordance with Bragg's law and Snell's law, a phenomenon of color changes in other words.
Compare with the typical crystal that has a regular period in the length of the same wavelength region as the X-ray, the colloidal crystals have a periodicity in the same region as the visible light. Typical crystals diffracted X-rays and the colloidal crystal is a phenomenon that occurs in order to diffract light.
Additional explanation on light-fastness
*Notes at the time of material processing
Because of the high insulating property material, it cannnot be processed in the discharge processing machine such as a wire eletrical discharge machine.
Because it contains silica crystals in the material, the tool is easily wear out compare to the processing of the resin. We recommend the use of carbide tools.