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DIY Colorful Terrazzo Coasters using Jesmonite

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Terrazzo—that gorgeous, speckled material comprised of heavy chips of marble and colorful glass set into concrete—is currently dominating modern interior design. You see it on expensive kitchen countertops, luxury flooring, and high-end boutique home decor.

Unfortunately, pouring real concrete and grinding actual quartz and marble shards requires heavy industrial machinery.

However, you can completely fake the high-end terrazzo aesthetic directly on your kitchen table using a miracle material called Jesmonite. Jesmonite is an eco-friendly, water-based acrylic resin that sets rock-hard in twenty minutes (unlike epoxy resin, which takes days to cure and is highly toxic). By casting your own wildly colorful "chips" and suspending them in a stark white Jesmonite base, you can craft heavy, stone-like coasters that look unbelievably expensive. Here is the recipe.

1. The Material (What is Jesmonite?)

Jesmonite comes in two parts: a heavy, chalky white powder (the base) and a milky liquid (the acrylic binder).

When you mix them together at a precise ratio (usually 2.5 parts powder to 1 part liquid by weight), you generate a thick, smooth, pancake-batter-like liquid that pours flawlessly and cures into a rigid, cool-to-the-touch, ceramic-like stone. To build terrazzo, you must execute a two-step process.

2. Phase 1: Making the 'Chips'

You cannot buy pre-made "Neon Terrazzo Chips" at a hardware store; you must manufacture them yourself.

  1. The Small Batches: Mix three tiny, separate paper cups of liquid Jesmonite (powder + liquid).
  2. The Pigments: Add liquid water-based pigments to the cups. Create one cup of blinding Neon Pink, one cup of Deep Navy, and one cup of Mustard Yellow. You only need a few drops; the pigment is fierce.
  3. The Splat: Take a plastic sheet (a cheap plastic trash bag taped to the table works perfectly). Pour the three brightly colored liquids directly onto the plastic and spread them out with a spatula until they are incredibly paper-thin, flat puddles.
  4. The Crush: Wait 30 minutes for the colored puddles to completely dry into hard stone sheets. Peel them off the plastic. Put them in a ziplock bag and literally smash them with a rolling pin or snap them with your fingers until you shatter them into hundreds of tiny, brilliant, jagged "chips."

3. Phase 2: The Final Pour

Now you have a massive pile of wildly colorful, broken stone confetti.

  1. The White Base: Mix a massive, fresh bowl of beautifully pure White Jesmonite (use no pigment).
  2. The Suspension: Dump your massive pile of colored pink, navy, and yellow shattered chips directly into the white liquid batter. Stir it aggressively so the chips are completely suspended in the liquid.
  3. The Molds: Place cheap, reusable silicone coaster molds (circles or hexagons) perfectly flat on a table.
  4. Pour the thick, chunky, chip-filled liquid directly into the silicone molds. Tap the molds violently against the table for thirty seconds to force any trapped air bubbles to the surface to pop.
  5. Wait exactly 45 minutes for the coasters to generate heat (an exothermic reaction) and cure rock solid.

4. The Reveal and the Sanding

When you peel the silicone mold away, you might be disappointed. The coaster will look like a flat, boring white puck. The beautiful colored chips are hidden microscopically beneath a thin skin of white Jesmonite.

The Grinding Grind: 1. You must heavily wet-sand the coaster. 2. Take a piece of coarse (80 grit) waterproof wet/dry sandpaper. Dip the coaster in water, and aggressively scrub the top surface by hand (or use an electric sander). 3. The sandpaper quickly grinds away the thin top layer of white, violently exposing the massive, embedded chips of colorful pink and navy stone trapped inside. The terrazzo pattern magically reveals itself! 4. Wipe it clean, let it dry, and seal it with a beeswax polish to protect it from coffee stains.

Conclusion

Faking terrazzo is arguably the most satisfying material craft you can attempt.

By casting ultra-thin sheets of intensely dyed Jesmonite, shattering them into chaotic shards, burying them in a liquid white binding matrix, and aggressively sanding the cured slab to reveal the buried gold, you can manufacture high-end architectural decor while sitting on your couch. Mix the batter and start pouring!

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