This one gave me fits! Just to let you know, you can NOT color key lime icing lavender/violet/purple with Wilton gel color. I'm guessing powder color will work, but I've not given it a try. This blue is what color I finally ended up with after two tries with 2 different jars (1 brand new) of gel color. Had to add Icing White White (which I don't really like to use) to get this color and salvage the icing. Luckily this was a giveway for a surprise party for our agency director so I didn't have specific colors I HAD to use. I used cocobean's Key Lime cake/buttercream recipe. Since it's gotten so hot and humid down here (96 degrees with about 110% humidity :)) I'm struggling with the buttercream. The flowers fell off right after I put it in the fridge and had to do a repair the next morn -grrrrr!