Quoted By:
The mainline Pokemon games started off being named after colors (Red, Green, Blue and Yellow), then a color/mineral hybrid (Gold/Silver). This was
Satoshi Tajiri's original intended conclusion to the series, but since the franchise had become such a massive worldwide success, GameFreak decided to keep making Pokemon games. Crystal was mineral/gem. Ruby/Sapphire/Emerald were named after gems. And Diamond being the hardest and most valuable mineral.
