What’s the default color for placeholder text in UITextField?

The colour is #C7C7CD (r: 199 g:199 b: 205) (as what pterry26 said)

and the font-family is HelveticaNeue-Medium and size is 16

Note that this is a guess at what the color looks like on a screen. For the actual values, simply inspect the Apple code for attributedPlaceholder.