Abstract: A molded fireplace construction whose firebox has an outer wall comprised of a mixture of magnesium oxychloride, organic resin and a fiber reinforcement such as fiberglass, an inner refraction liner of slate dust and magnesium oxychloride and an insulator therebetween comprised of magnesium oxychloride, expanded mica or slag and microballons. The completed construction has an inner liner resistant to abrasion and heat, an effective insulating layer and an outer structural layer which can be decorative or merely functional. In the exhaust system for the firebox, the outer two layers can be used without the inner refractory layer. The fireplace construction is fabricated for easy assembly and replacement of portions thereof should that ever be required.