After getting the money from selling her hair, Della looks for two hours to find the perfect Christmas gift for Jim, "a platinum fob chain simple and chaste in design, properly proclaiming its value by substance alone, and not the meretricious ornamentation." The fob reminds Della of both Jim and his watch; the chain possesses "quietness and value;" its appeal and worth are proclaimed in its ________ and unadorned design.