One of the fun parts about this blog has been looking up things about glassblowing that even I didn't know. So today I'm going to answer a question that I was actually curious about, inspired by the use of Gilson Opals in my work.

How Are Gilson Opals Made?

Use in Glassblowing

In glassblowing, we use what are called Gilson Opals instead of raw opals. The reason for this is that raw opals will crack if they are placed inside of molten glass. I suspect this is because they contain water, and also like most organic things they do not heat up evenly, which creates stress inside the glass.

I'd been using these for years, until I thought, how exactly are synthetic Opals made?

The Gilson Process

I was able to find an answer here. Apparently Pierre Gilson Sr, a French scientist, found a way to create synthetic opals in 1974. He started by lining up silicon spheres in a lattice that would mimic the light diffracting properties of opals, which is what gives them the ability to turn colors depending on how the light hits them.

Then he placed them in a silica gel, which hardens and over the course of a year or two become complete products. The result is an opal which contains all the same elements of raw opals except that they do not contain water. They are also made to be perfectly symmetrical in both shape and composition, which makes them ideal for glassblowing.

So now we've both learned something today! I've made many pieces of beautiful jewelry using synthetic opals, order one yourself today! 

But you may say to yourself, I don't care about lab created opals, I wanna know how natural opals are formed. Find out more here.