Samsung Galaxy S8 for comparison.

Specifications
Body - 162 × 80 × 10 mm (6.4 × 3.2 × 0.4 in)
Display - 7in - 99% Screen-To-Body-Ratio

Reasoning
The end caps are normal, industrial aluminum.
The back and front of the phone is one clear aluminum sleeve.
Clear aluminum is newer developement, and thus is fairly expensive. Given the rate at which we have advanced as a species, clear aluminum should be cost effective enough for future commercial manufacturing.
The end cap will be held on by 4 screws; this allows for this allows for easy repairs, as the two caps are connected to the internals, which are layed side by side; the securing screws are set into the main housing.

Features
Top Cap - The center third is a sensor that will serve as the power "button."
Bottom Cap - Three divots can be found on it's surface. The center divot will serve as a magnetic latch for a special charging cable. The left and right divots will serve as magnetic latches for special AUX cables.
Main Housing - This will house the phone hardware, which will include the sound casters, allowing for a smooth, uninterrupted housing. The back of the housing is frosted, keeping the internals hidden.