The clear epoxy resin cast glass gem mosaic coaster suspends flat-backed, iridescent glass nuggets inside a crystal-clear, heat-resistant resin disc. This technique creates a smooth, level tabletop surface that mimics sea glass embedded in clear water, allowing the rich colors of the glass gems to shine through with high optical clarity. The solid resin encasement locks the glass pieces permanently in place, making the coaster completely waterproof, washable, and resistant to heat from hot coffee mugs. Arranging translucent aqua, cobalt, seafoam green, and amber glass nuggets in an organic mosaic layout produces a coastal, spa-like aesthetic that elevates everyday beverage service.
Begin by setting a four-inch round or hexagonal silicone coaster mold on a level work table, spraying the interior lightly with mold release spray. Arrange flat-backed colored glass gems inside the bottom of the silicone mold, placing the smooth, flat faces downward and leaving narrow one-sixteenth-inch gaps between stones. In a clean plastic measuring cup, mix equal parts of two-part clear casting epoxy resin and hardener, stirring slowly for three full minutes with a flat wooden stir stick to minimize air bubbles. Slowly pour the mixed clear resin over the arranged glass gems until the liquid level rises just above the top edges of the glass pieces. Sweep a handheld heat gun or culinary torch on low heat across the liquid resin surface two inches above the mold to pop any rising air bubbles. Allow the resin coaster to cure undisturbed for twenty-four to forty-eight hours before gently peeling the silicone mold away to reveal the glossy, glass-embedded drink mat.