The photograph shows what appears to be the same mold that cropped up on Sunday, but with a white iPhone 4s posed next to it for scale. The picture was first published by French blog Nowhereelse.fr.
The publication believes that the mold, which is tapered, will be used to form the rear casing of the so-called iPhone 6. The outermost rim of the mold is slightly taller and wider than the iPhone 4s next to it, indicating that the casing will be larger than current models.
Rough measurements of the mold, arrived at by superimposing a photo of Apple's iPhone 5s and resizing it using the pictures iPhone 4s as a guide, seem to suggest a device with a 4.7-inch display. That matches up with previous whispers, including a recent prediction from well-connected analyst Ming-Chi Kuo of KGI Securities, though the measurement does assume that the face of the next-generation handset will not undergo significant changes.
Apple is widely expected to unveil two new iPhones with different screen sizes this fall in a nod to worldwide consumer trends toward larger-screened handsets. In addition to the rumored 4.7-inch display, the company is also thought to be preparing a much larger 5.5-inch "phablet" variant.