I 2nd the erkel. As well I have seen blue cheese and columbian gold turn some amazing colors. tho final coloring has a lot to do with their feed schedule as well. If u cut nutes early ur more likely to get a deficiency or two ideally N and P for best flavor and color. N deficiency will give it a better taste and a slight p deficiency can bring out many colors more commonly shades of blue red and purple. Tho genetics do play a role. Ie one of my two erkel moms will turn purple reguardless of nute or temp and the other one won't even lighten up by the end