Spearmint is a Soft Calf color from Resort 2004, members sometimes come across items in this color at outlets (older styles/colors and leftovers from stores get sent there). You can check back every now and then, some wonderful members will post information when they spot them. You can then contact the store directly to order it. Good luck. =)
^^ Some Marc Jacobs boutiques might have Spearmint Venetias left. You can contact any MJ store, a SA will be able to look up their inventory for you. If you prefer to inquire via e-mail, PM me for my SAs' contact info.