Specially formulated black matte interior enamel of each piece contains traces of quartz, giving it additional heat resistance and a rougher surface resulting in better browning. Grenadine, Sapphire, Basil and Graphite colors feature a multicoat enameling, which creates a glossy, vibrantly colored "majolique" finish that resembles fine ceramics. Lid knob on Matte Black 5 3/4-Qt.Oval Oven is brass; lid knobs for all other colorways are made of nickel-plated brass. Matte Black color selection features a low-gloss matte finish. Heavyweight enameled cast iron transfers and retains heat evenly. Resistant to rust, chipping and cracking, the coating requires no additional seasoning like some other cast-iron pieces. When using high heat, bring pans slowly to a high temperature. Use plastic, wood or nylon utensils only; metal utensils may damage enamel. Enamel may chip or crack if banged against a hard surface. Handles and knobs can become very hot. Ideal for use on any cooktop, including induction; not recommended for glass stove tops. Oven and broiler safe up to 500°F. For best results, use low to medium heat.