How To Make Glow in the Dark Opals (Glowing Fauxpals)

Yes, I made up the word “fauxpals”. Writers make up words all the time 🙂 This is a super-simple tutorial for making glow in the dark opals out of resin. You don’t have to make them glow, but it’s a cool effect, so why not?

There are two big benefits to these jewels, aside from the glowing aspect. (1) Unlike regular opals, they won’t eventually lose their water and thus their opalescence and (2) These are way less expensive! True opals will cost you a mint. They are a naturally soft gemstone, so you don’t lose utility using resin instead of natural silicate.

Glow in the Dark Opal Materials

• resin
• mixing cup
• stirring stick
• mold
• iridescent cellophane
• scissors
• glow powder

You can use any resin you like, so long as you keep its properties in mind during the project. Primarily you’ll be interested in the resin’s clarity, working time, and viscosity. I used Clear Cast via Amazon because I like that it’s crystal clear and that I can work with it for several minutes before it gets too thick.

I use little plastic medicine cups and coffee stirring sticks to mix the resin and inclusions. Use whatever works for you.

With the resin I used, cellophane works for this project because it stays suspended in the resin. That produces a nice three-dimensional iridescence. I tried iridescent and holographic glitter, but they were too dense and always sank to the bottom of the shape. This is problem because it makes the “opal” look flat and because it reduces the amount of light that gets to the phosphorescent powder. Some glitter isn’t color-safe in the organic solvent, so the color may run off or react unpredictably. I’m not saying you can’t use glitter, but if you do, you need to watch the viscosity of the resin and wait to pour it when it’s thick enough to suspend the particles.

Phosphorescent (glow) powder also comes in different sizes. Large particles glow brightly, but sink in resin. Look for a fine powder for this project, which produces a uniform glow throughout the opal, not just on one surface. I like the day neutral powders, which appear translucent in ordinary light. If you use a colored powder, your opal won’t be as clear or glow as brightly. Green, aqua, and blue powders glow the most brightly, so they are preferable to other colors. I’d avoid red, orange, or any of the zinc sulfide powders because they are opaque.

Let’s Make Glowing Opals!

Alright, so I said it’s super-simple. Basically, you mix resin, add cellophane and glow powder, pour the resin, and you’re done! However, you can save yourself some pain and suffering if you read through these tips before you start.

1. First, you need to prepare the opalescent part of the opals. This involves snipping the cellophane into tiny pieces with scissors. Start by crumpling one or more pieces of iridescent cellophane. Place them in a shallow bowl and snip at them with scissors until you have small, irregular flakes. Larger bits of cellophane look cool, too, but when you put them in the resin, they’ll un-crinkle and may extend out into the back surface. It’s not a big deal, but if you want a smooth back to your shape, it’s better to know about this in advance. If you’re using colored cellophane, you might want to test it to make sure it’s not going to do something funky in your resin. You can probably get away with swabbing the surface with alcohol to see if color bleeds, rather than making up a whole batch of resin.
2. Make sure your mold is clean and dry. Technically, you don’t need a mold. You could just pour a blob of resin on a flat surface or you could dome it over a flat shape. Clearcast is not a self-doming resin. Actually, it shrinks back a bit when it cures, so how you make your shape depends partly on your resin.
3. Mix the resin. Add some cellophane and some glow powder. I say “some” because it’s completely up to you. You’ll see how the powder and cellophane affects the opacity of the resin, so it’s just a judgement call.
4. Pour the resin. As I mentioned, if your cellophane or glitter or whatever you’re using sinks to the bottom of the mixing cup, you may want to wait until the resin thickens. I pop bubbles using a quick pass with a lighter, but you can use a toothpick. Viscosity. Opacity. Phosphorescence. Polymerization. SCIENCE!
5. Let the resin cure completely before removing it from the mold. After it’s cured, you can polish it or leave it, as you like. Some of the pieces I’ve tried were matte coming out of the mold. That effect is nice, since it mutes the opalescence and scatters the glow. But, if you have a matte piece and want it shiny, simply paint over it with fresh resin, Modge Podge, or a related clear coating. I do not recommend nail polish, since it may yellow or flake over time.

What To Do With Glow in the Dark Opals

I’ve used the technique to make cabochons for jewelry and crafts, paperweights, and a pretty night light for my bathroom. You can use cellophane in the glowing ring project to add more daytime interest to that item. I think fauxpals would make pretty suncatchers and holiday ornaments. What are your ideas?