Steps To Grow Synthetic Opals With A Brilliant Play-of-ColorBlack Opal, White Opal, Crystal Opal & Fire Opal. Synthetic Opal Manufacture.
Synthetic Opal - Preparation of Non-Porous Spherical Monodisperse Silica Nanoparticles
Our silica particles are manufactured in-house by utilizing our proprietary process. For the manufacture of synthetic opal we produce particles in a size range of 250-320 nm. It is crucial that the particles are spherical and highly monodisperse. If the particles are oddly shaped and/or polydisperse no or only dull colors can be observed. Therefore, every single batch of particles is carefully monitored to maintain the necessary high-quality level.
Scanning Electron Micrographs Of Silica Particles (3D Ordered, Hexagonal Close-Packed Array)
Synthetic Opal - Colloidal Crystallization.
All currently available synthetic opals are produced by sedimentation of monodisperse silica particles under gravity. Without exception!
The particles are finely dispersed in water and afterwards left for sedimentation, which is a long, time-consuming process. To avoid defects, this process should take place without any mechanical disturbance. The growth of synthetic opal under sedimentation is a process of hetereogeneous crystallization and starts with the formation of an ordered layer of particles at the bottom of the vessel. With ongoing sedimentation, layers of hexagonal ordered particles stack on top of each other and the final result is a crystalline sediment with the typical striated/columnar pattern parallel to the growth direction. The dimensions of the columns can be varied by changing the concentration of particles - lower concentrations lead to larger columns (and a prolonged sedimentation time).
Sedimenting Monodisperse Silica Particles (Test Tube)
Synthetic Opal - Sediment of Monodisperse Silica Particles. The Arrow Indicates a Narrow Band with Growth Distortions, Caused by Movement.