In fashion jewelry manufacturing, there are three commonly seen types of the post/stick part design. To the customers they may not even notice the difference at the beginning, but to the brand owners, this may be very critical to the quality of your design.
#1 The Lowest Cost (circled in red): Brass body part with brass post, and plating them together.
In this type, you are not able to tell the difference from the look, because the products are plated after assembled. The problem of this type is that the wearers are easily get allergic reaction because some of the metal elements in the alloy post are hyper-allergic.
As a responsible manufacturer, this is the correct answer in an alloy design fashion jewelry earrings. Plating the mix-materials assembled product is costly and tricky because you need to cover one material to complete another material’s plating preparation (some process may not be needed the other material)