Our Jewelry Association has access to the finest Diamond Manufacturers in the US and worldwide. Connect with our Members & Explore their collections. The members of The Plumb Club account for a significant percentage of the domestic fine jewelry market. Each of the members in this exclusive club are highly skilled, transparent, and professional. This exceptional standard of operation is ensured by the implementation of the Code of Responsibility – a guideline and agreement signed annually by each member. This code allows the Plumb Club to connect retailers and jewelry & diamond manufacturers in the US in a professional, transparent, and rewarding way.