The materials mentioned in the patent are zirconia and alumina. If you're a regular Joe like myself, those names mean nothing to you. What you should is know that they'll allow for a cheaper iPhone body, and zirconia supposedly allows radio waves to pass through it, so it would work just fine for electronics.
Apple has yet to announce the dates for this year's Worldwide Developer's Conference, but assuming it keeps the same schedule as last year, that would put the iPhone 5S announcement right after it.
via Slash Gear