How to Make Jesmonite® Jewellery (Earrings & Beyond)

It is a lovely craft to start with because the pieces are small, the materials go a long way and you can experiment with colour on almost no budget. Ready to cast your first pair of earrings? Let us walk through it.

Why Jesmonite® (and Reslin®) for jewellery

Jesmonite® AC100 is a water-based, two-part material: a mineral Jesmonite® base powder mixed with a liquid acrylic. It is non-toxic and free of solvents and VOCs, which matters when you are working at a kitchen table rather than a workshop. It sets quickly, takes pigment beautifully and gives you a matte, stone-like feel that suits terrazzo, marble and colour-block earrings.

For jewellery you want AC100 specifically. It is the beginner-friendly, indoor decorative option and it captures the fine detail of small moulds cleanly. You can explore the range on the AC100 page.

If you love translucent, see-through pieces or want to embed dried flowers, Reslin® is a lovely alternative. It is a 100% plant-based casting resin and the first 100% plant-based alternative to epoxy, made from linseed oil and an activator from sugar beet molasses. Natural Reslin® has a warm yellow tint and is see-through rather than water-clear like epoxy. It is best handled with gloves as it can be sticky, and it blends readily with pigments, dried flowers and fillers, so it opens up a whole different look for pendants and statement pieces. Learn more in our guide to what Reslin® is.

Choosing jewellery moulds

The mould shapes your piece, so this is where the fun starts. Silicone moulds made for small castings give you crisp edges and release easily. Look for shapes sized for earrings, studs, pendants and charms rather than homeware.

Browse the dedicated jewellery moulds to see what suits your style. A few things worth thinking about:

• Scale: smaller cavities use very little material and dry faster, which is ideal when you are learning.
• Depth: shallow moulds are easier to fill without trapping air; deeper ones give you more presence but need slower pouring.
• Pairs: for earrings, a mould with matching cavities helps you cast a set that looks balanced.
• Detail: fine textures show every colour swirl, so pigment choices matter more with detailed moulds.

What you’ll need

You do not need much to begin. Most of it fits in a small box on a shelf.

• A Jesmonite® AC100 base powder and liquid (or a starter kit that bundles them together).
• Silicone jewellery moulds.
• Liquid pigments to colour your mix. A little goes a long way, so one small bottle lasts a surprisingly long time.
• Accurate digital scales, mixing cups and stirring sticks or a small spatula.
• Findings: earring hooks or studs, jump rings, pendant bails and posts.
• A toothpick for popping surface bubbles, and sandpaper with a sanding block for the edges.

If you would rather not gather everything piece by piece, an AC100 starter kit pulls the essentials together in one go, which is the simplest way to get started.

Step-by-step: casting earrings or pendants

Small pieces are forgiving, but a little care makes them look professional. Here is the routine.

1. Work out how much to mix. These moulds hold very little, so a small batch is plenty. For AC100, fill the empty cavity with water and note that volume, then add about 10% spare (some mix always stays in the cup). Divide that figure by 2 to get the amount of Jesmonite® liquid you need, and multiply the liquid by 2.5 to get the amount of Jesmonite® base powder. Most of our own mould product descriptions also list the amount you need, and an online Jesmonite® calculator or the Jesmonite® app can do the sums for you. See our full guide on how much Jesmonite® you need.
2. Weigh accurately. AC100 uses a mix ratio of 1 part Jesmonite® liquid to 2.5 parts base powder by weight. Getting this right is the single most important step.
3. Add colour. Stir a small amount of pigment into the Jesmonite® liquid first, then combine with the powder. For a marble effect, mix two colours and swirl gently rather than blending fully. For a real terrazzo look, fold small Jesmonite® chips you have made yourself into a fresh mix for that speckled finish.
4. Mix thoroughly. Combine until smooth and lump-free. Scrape the sides of the cup so nothing stays dry.
5. Beat the bubbles. Pour slowly in a thin stream from around 10 cm above the mould. Gently tap and vibrate the mould on the table so trapped air rises to the surface, then pop any surface bubbles with a toothpick, this is the main way to get a clean cast. Only for moulds with a lot of fine detail, you can first brush a thin layer into the cavity, but for most pieces this isn’t needed. For larger pieces or very detailed moulds, a vibration plate makes releasing bubbles even easier.
6. Set the findings (optional). If you want a post or loop cast directly into the piece, press it into the surface once the mix begins to thicken so it holds in place.
7. Let it firm up. AC100 demoulds in around 30 minutes. Do not rush it, but do not leave small pieces sitting far too long either.
8. Demould gently. Flex the silicone and ease the piece out. It will feel firm but keeps getting stronger over the next 24 hours as it fully cures.

Chalky or soft results almost always mean the mix ratio was off or the scales were inaccurate. Too much Jesmonite® liquid gives a soft, chalky cast; too little makes it thick and fast. Weigh carefully and you will avoid nearly every common problem.

Adding findings and finishing

This stage turns a little cast shape into a finished piece.

Finish the edges. Small castings often have a faint seam where the mould halves met. Sand it as soon as you can after demoulding, while the cast is still relatively soft and easy to work: start with a coarser grit to knock back any high spots, then move to a medium grit for a clean edge. A medium sandpaper is ideal for that final pass. Sand lightly and check often.

Attach the findings. Our jewellery moulds leave a small hole in each piece, so you can simply thread a jump ring through it and add your earring hook or pendant bail, no glue needed. Match your metal colour across a pair for a tidy finish.

Seal if you like. Jewellery does not usually need sealing, but if you want a subtle sheen or a little extra protection you can add a light coat of acrylic sealer once the piece has cured. AC100 takes an acrylic sealer in satin or gloss. Let each piece cure for a full day before sealing or wearing. See our guide to sealing Jesmonite® for the method.

Because Jesmonite® is light in the hand, even chunky earrings stay comfortable to wear, which is part of why it works so well for this.

Try it yourself

Making your own jewellery is one of the quickest, most rewarding ways into casting. Start small, play with colour and build up a collection you actually want to wear or gift. Pick up a set of jewellery moulds and an AC100 starter kit, and cast your first pair of earrings this weekend.