Abstract: A furnace is provided generally including an upper heating chamber and a lower work base or firing platform. The upper chamber provides the main source of heat to the materials to be heat-treated. The upper chamber contains a muffle within which is located a heater ring assembly. The heater ring assembly is located in the middle to upper half of the muffle and includes an annular heating element that is located between an outer insulation ring and an inner quartz sleeve. A cavity or channel extends through the muffle into which insulation materials and the heater ring assembly is located. The channel area in the muffle below the heater ring assembly allows for the placement of the firing platform therein. The firing platform includes insulation material and a heating element located in the upper portion thereof.