Another thead in a different forum about a completely different matter got me wondering about this.
Less pigmentation makes hair go white and I suppose gray hair has a bit more pigmentation than white. But where does the shine of silver hair come from?
Doesn’t dark hair turn gray, and light hair turn silver?
Not necessarily. I have dark-to-medium ash-brown hair, and my gray hairs are quite definitely silver/white, not gray. I know this because I pull them out and glare at them closely. 
Hair shines when it’s healthy and not dried out or abused, so I’d assume that the gleaming head of silver hair is healthy hair that is adequately moisturized. I know plenty of people with silver-white hair that does not shine silver, it just looks like non-yellowish white hair.
Not really. The white hairs that I have are completely white not grey and the rest of my hair is black.
Not necessarily. My mother had dark brown hair, and it’s now a brilliant silver. Mine looks to be going the same way, yay!