I use AIPoly. However, as someone born blind, I have to take all of these colour identification apps with a grain of salt. Apparently, lighting can effect colour quite a bit; an object that looks one colour under one type of lighting, can look like it's a different colour under another type of lighting. As I've never been able to see, I don't understand how this works, at all. I find when I ask a sighted person, they can give me a more reliable answer, that seems to be more "true" than the app does. I assume you're better able to take into account the type of light, and better judge what the colour "really" is. For given values of "true" and "really", I guess.

I don't personally use these so I don't know how great they are, but there are a few apps with similar concepts. ColoredEye will read off colors (says primarily for colorblind individuals but I mean I assume the same principle applies). Then there are a few that will read labels, scan barcodes, tell you what denomination of money you have, etc. Here's a few I found: Digit-Eyes Lite, TapTapSee, Seeing Assistant Home, and NantMobile Money Reader. All of these are on the Apple app store, I have no idea about Android though.

As others said there are apps but they're hard because they depend on lighting and a clear picture.

You can buy a device called a color identifier that's really accurate and good for things like clothes. They cost a few hundred dollars unfortunately, because the market is small.