I was wondering if anyone knows of a blue fleshed potato that turns a beautiful vivid turquoise or robin-egg blue when cooked. It was a total surprise to us because they were purple when raw (with, I think, a bit of white streaking) but I don't remember the skin color- but likely purple too). My brother bought them about 35 years ago at the local farmers market because he thought purple potatoes were funny (before I ever thought of growing my own heirloom potatoes but now I wish I knew what variety it was so I could get some seed potatoes). Any blue or purple potatoes I have found so far either stay purple or turn grey when cooked (although some varieties of the grey ones turn a pretty light lavender the next day after sitting in the fridge overnight) but none are as beautiful as those robin-egg blue ones.