In today's keynote, Apple showcased videos about the metal refining processes of both the stainless steel Apple Watch and aluminum Apple Watch Sport, but omitted the solid gold Apple Watch Edition video, which appeared on Apple's website following the event.
Narrated by Jony Ive, the video provides an overview of the gold refining process, which yields a compound up to twice as hard as standard gold. The custom alloys of yellow and rose gold using precise amounts of silver, copper, and palladium to produce a specific hue of each color of gold.