The Apple iPhone 6C is slated to be released in March 2016 and according to the recent mockup of this upcoming Apple phone, one might see same color choices as the current generation iPod Touch. This means you could see the Apple iPhone 6C in silver, space gray, gold, rose gold, pink, and blue colors. 
Apple iPhone 6C specs
The 6C will come with 2GB RAM, 4 inch display, NFC for Apple Pay and a larger 1642 mAh battery but will lack 3D touch which is the main selling point of iPhone 6S. However, it will have touch ID support – something which the current gen iPhone 5C lacks. It will be powered by Apple A9 processor to keep everything running smoothly.
The iPhone 6C will have casing similar to the iPhone 5S but will boast the same 2.5D glass being used in the iPhone 6 and iPhone 6S. At the same March 2016 event, Apple is also expected to release second generation Apple Watch.