Refractory object may include Al ₂ O ₃ of at least 10% by weight. In one embodiment, the refractory body may further include a dopant containing an oxide of a rare earth element, Ta, Nb, Hf, or any combination thereof. In another embodiment, the refractory body has a mean creep rate properties that do not increase the grain size is more than 500% during the sintering, an aspect ratio of less than about 4.0, about 1.0x10 ^-5 μm / (hr x μm) less than, or in of it may be of any combination. In a particular embodiment, the refractory block or object may be in the form of a refractory glass forming overflow block. Glass forming overflow block may be useful to form a Mg-Al-Si glass sheet. In a particular embodiment, the layer containing an Mg-Al oxide may be formed initially along the exposed surface of the Al-Mg-Si glass forming overflow block in the formation of the sheet.