How to synthesize opals?

Once the electrolyte is mixed into the opal dirt, colour starts to form within four to six days. Seams of opal then actually grow, identical in shape and form to that found in the ground, some with colour and some without, the process taking about three months. read more

It is softer than natural opal and exhibits lizard-skin iridescence, a scale-like pattern that is close to the appearance of natural opal but is still noticeably different. Synthetic Opals The basic process of opal synthesis consists of three stages. read more

TalonD, I have made synthetic opal(ine material - ie: not hardened) using a process similar to the one you give. I used TEOS, reagent-grade ammonia, reagent-grade alcohol (denatured, I think), and super clean water ("triple distilled" or some such). read more