*Last Updated: 12/07/2021

Opal is a very delicate stone, they chip easily, some can lose their color if you get them wet, along with a whole list of issues you can run into when working with these lovely stones. So when you start introducing copper electroforming solution to your opals it can turn into a disaster. But it’s not impossible to electroform opals into your jewelry designs. I have spent hours researching opals and their chemical composition and how it reacts to copper sulfate/sulfuric acid.

*Copper Electroforming Using Opals - Maker-Monologues.com*

Let’s talk about two types of opals:

Hydrophane Opals
Non-Hydrophane Opals

In this article, I’m going to cover only opals from Australia and Ethiopia because those are the two main sources of opal, and they’re what I see you all asking about the most.

Hydrophane Opals

Hydrophane means water-loving. Hydrophane opals are very porous and will soak up any type of liquid they come in contact with. This can cause the opals to temporarily lose their color when they come in contact with water, but when it fully dries the color will come back.

Ethiopian Opal

Ethiopian (Welo) opals are mostly hydrophane and more porous than Australian opal. If your Ethiopian opal gets wet it will almost always turn a translucent color and lose its color play. But they will usually get that color playback after having been dried out for anywhere between a few hours to a few weeks.

The amount of water and porosity of Ethiopian opals vary, so some opals may not be affected as intensely as others by being submerged in water. This chemical composition of Ethiopian opals makes them difficult and tricky to use when making electroformed jewelry.

However, it’s not impossible to use this brightly colored opal in copper electroforming. It just needs more care and prep time before soaking it in the bath. Because of their hydrophane nature, you want to seal your Welo opals really well before electroforming them. The type of sealant you use is very important, you don’t want to you any water-based sealants as the opal will just soak it up.

Sealing Welo Opals

There are many ways to properly seal a Welo opal before electroforming them. The most common way is to use a combination of clear nail polish and frisket or liquid latex:

Paint the entire opal with 3 coats of clear nail polish, letting it fully dry between coats. (To do this, paint the bottom and sides of the opal while the top is laying on a surface, let dry, then turn it over and paint the top and overlap the sides. Then do this two more times)
Then you can go ahead as usual with gluing the stone to your ring shank, pendant bail, etc.
Next, apply the epoxy to fill any gaps between your copper ring shank or bail and the opal.
Apply your conductive paint wherever you want.
Then do 3 coats of liquid latex on the area of the opal you didn’t apply conductive paint, letting dry between each coat. So the latex should be painted up to the point where you painted the conductive paint.
Electroform as usual.
Once you’re finished electroforming you can polish your piece with the layers of sealant still in tacked, some even toss it in the tumbler. Then you can peel the latex off. Then take some non-acetone nail polish remover with a q-tip or toothpick and remove the layer of nail polish.

Non-Hydrophane Opals

Opals that are more solid, less porous, cannot soak up any liquids, and will do just fine if wet.

Australian Opal

Australian opals have more water content and are non-porous making them less hydrophane. They will not soak up and any type of liquid, unless it has a crack in it then it will act as the Ethiopian opal and lose its color until it dries out. These types of opals are easier to work with when creating electroformed jewelry.

Lighting Ridge Opal Ring, Oxidized Copper

Sealing Australian Opals

Australian opal doesn’t need as much prep, with some having luck in doing nothing at all in protecting the opal, but I highly recommend sealing them. With Australian opals, you can get away with just doing 1 layer of liquid latex while some have success with just doing a couple of coats of clear nail polish. Then using the same method mentioned in step 7 of the Ethiopian opals to remove the layers of sealants.

How To Tell If An Opal Is Hydrophane

Add a drop of water to the surface of your opal, if the opal quickly soaks up the water you know it’s hydrophane. Take extreme care in sealing it before creating a piece of electroformed jewelry with it.

Opals are a wonderful, magnificent stone, and with the right care, prep and patients you can use them in your jewelry making to create stunning, one-of-a-kind designs. If you have any additional questions about using opals in your elctroformed jewelry leave a comment below and I’ll be sure to answer it!