Long ago in a previous life I worked in print shops. Part of that world is using the Pantone colour system for all sorts of things and Pantone is the industry fixture for colour recipes and colour forecasts. Carolyn Good has, for years, published a colour system for clayers based on the Pantone colour system which she regularly updates as the Pantone folks release their seasonal forecasts. Particularly liked what she calls her version of Iced Coffee, used in the above demo projects. You can see can see a quick breakdown of how she made the iced coffee “yarn”. Iced Coffee was part of Pantone’s Spring 2016 release which she has details about right here.
Why do I mention the Pantone index for colours? Because, as you advanced in polymer clay, colour choices and mixes are an important part of claying and if you’ll be doing this for a while you may want to be able to replicate colours over time. Part of that is keeping notes of what you mix to get those colours. Carolyn’s system is one way to take advantage of someone’s system all in one. Another talented clayer’s version of the same sort of idea is the one CraftsByChris has in her Etsy shop.