This week, I had the same situation of stain on my white Formica countertop. After trying bleach, Fantastic, lemon juice, baking soda and Soilmaster, all to no avail, I used Whink's Rust and Iron Stain Remover and in 1/2 hour the stain was removed. On a colored countertop,I would suggest a small test spot in an inconspicious area for colorfastness before using this product.
To prevent further such stains on my white countertop, I have now sealed the countertop with a commercial grade liquid sealer (available from Sysco Distributors). I have previously used Gel Gloss for sealing, with minimal results. I hope this information will be helpful to you.