Envision a mixed media collage that brings together peculiar elements of the steampunk culture and profession of a mortician. In this outlandish fusion, portray a Caucasian female mortician donning an antiquated, intricately decorated mask and an added third arm, which is a marvel of mechanical engineering. Ensure the shoulder-mounted, articulated third limb is clearly robotic, showcasing an array of tiny gears, levers, and steam vents, emblematic of the steampunk aesthetic. Her conventional two human arms perform their tasks diligently while the robotic appendage adds to efficiency. The environment should be filled with antiquated instruments, echoing both her profession and the vintage nuances of steampunk.