A clear ice maker assembly for an appliance includes an ice tray rotatably coupled with a housing and horizontally suspended within an interior volume of the housing. The ice tray includes a metallic ice forming plate with a bottom surface, a substantially planar top surface and an edge portion. A containment wall extends upward from the top surface along the edge portion. A grid having at least one dividing wall extends across the top surface between the containment walls. A fluid line extends into the housing and supplies water to the top surface of the ice tray to be retained by the containment wall and the grid. A cooling source is thermally coupled to the bottom surface of the ice forming plate. The containment wall and the grid have a material with a lower thermal conductivity than the ice forming plate.