In terms of weight, gel-coated shower trays are between the other two types: ceramic and acrylic. Ceramic, or fireclay, trays are the heaviest and are suitable for frequent public use because of their resistance to wear. The lightest trays are made of acrylic with wood reinforcement. Gel-coated -- or resin-stone -- shower trays, combine solid stone matter with resin, a substance that serves as the basis of plastic, in a product more durable than acrylic but not as tough as ceramic.
Manufacturers line a mold with gel before pouring the stone-resin mixture into it. After the blend sets, it slips out of the mold with a glossy surface, and the gel forms the top layer of the tray.
Gel-coated shower trays are available in rectangular, square and irregular shapes. The trays range from just over 3 feet to 5½ feet on their widest side.
The gel on the stone-resin shower trays is a soft substance that loses its shine with use. Eventually, the bottom of your shower box will start looking dull. A more serious issue is the fact that gel-coated shower trays are slippery and may cause you to fall. To minimize the risk, manufacturers use molds that create textured surfaces.