Black opals are one of the most valuable gemstones because of their rarity and dark, iridescent beauty. I've been working on casting realistic faux gemstones with resin and have come up with a black opal I'm really proud of. Since I work a lot with natural gemstones, realism is important to me.

Aside from the enormous difference in cost, one of the great parts of using resin is you can make your opals in any shape or size. I've decided to use heart post earrings to show you my technique.

Step 1: What You Need

A bezel or bezels of your choice (see the next step to help choose)

Casting resin - any kind works fine, it's mostly just a matter of drying time (I used polyester)

White glitter (not fine, you'll want some texture)

Pearl powder colorant

Black enamel (nail polish is fine)

Iridescent acrylic or enamel paint - 1-3 colors

Tweezer

Toothpicks

Wax paper

Mixing cups (Dixie cups work well)

Lots of patience

Step 2: Bezel or Mold?

There are generally two ways I cast faux gemstones using resin.

The first is to pour resin into a mold and pop the "gems" out when dry. This means the lowest parts of the design are what shows on the front when removed from the mold.

The second casting technique I use is to pour resin into a bezel, which like a flat mold with a small lip. When pouring into a bezel the bottom of your design stays on the bottom. Resin stays in the bezel, which means you can make the "gem" the exact size of the ring, pendant earring, etc, that your making.

For this tutorial I've chosen to cast my opals in tiny heart bezels which are attached to earring posts. You can make your faux opals project using any size or shape bezel. If you decide to use a mold instead, remember you'll have to reverse the coloring steps.

Step 3:

Set your bezels up on something nonstick, like wax paper.

Since I’m using post earrings, I am poking each post into a piece of foam to keep my earrings stable.

Step 4: Base Color

For each bezel, paint a heavy coat of black enamel (nail polish) on the inside. While the enamel is still wet, sprinkle in white glitter using a tweezer. Repeat this for all the bezels you’re working with. Push ornery pieces of glitter down with a toothpick.

Allowed to dry fully.

Step 5: Small Batches

Do a few at a time so the enamel doesn't dry with out glitter.

Step 6: All Filled In

Step 7: Highlight 1

Now pick a color of opalescent paint - it can be either enamel or acrylic. And with a very tiny brush or your finger dab a very small amount in each bezel. The color should be very random. Do not overwhelm the black and glitter you already have.

Step 8: More Highlight Colors

Add one or two more colors, one at a time, very lightly.

Step 9: Wait

Allow everything to dry fully again.

Step 10: Ready for Resin

I rearranged my earrings to make pouring resin easier. Note the wax paper.

Step 11: Resin Layer 1

Mix a very small batch of resin (enough to fill 1/4 of each bezel). Add in a tiny amount of pearl color. The resin should still be see-thru.

Note: Prepare resin according to package directions

Step 12: Pour

Add a thin layer of pearly resin.

Step 13: Adjust

Use a toothpick to push the glitter into the resin and push the resin around.

Step 14: Resin Layer 2

Mix another small batch of resin and keep it clear. Add a thin layer. It's okay if this mixes a little with the first layer.

Allow the resin to set.

Step 15: Fill

Mix another batch of clear resin. Carefully pour to fill each bezel.

Step 16: Dome

As the resin thickens, slowly add one drop of resin at a time, until the surface forms a dome. Try not to overfill and drip over the sides. It's easier to add resin later if needed.

Step 17: Check

Look at the sides of the bezels and make sure all the tops are domed. Add more resin to any that are too flat. Try not to touch or move these now. (Some people put a dust cover over the wet resin.)

Step 18: Wait

Now be patient. Allow the resin to cure fully. The surface should be glassy and smooth. If you touch it too soon, you'll leave fingerprints. How long this takes depends on the resin and the temperature.