Adding a Product that Cannot be Purchased

[Acetylene]

This might be a strange request, but I am building a store for a woman who makes custom jewelry items. Most of the items she makes have set prices and I can just post them as a regular store item, but for one particular item, she wants to talk directly to the customer about a unique custom design. The price for this item will be determined by the customer's desires and will be unique for each design. Therefore, I want to post this product so that it is viewable in the catalog, but I do not want people to be able to buy it; they have to fill out the contact form to order it.

 

Is there a way to post a product that cannot be purchased?