Etched Structure Number 4One of a kind handmade necklace. Sterling silver pendant and chain Pendant dimensions: 1 x 1. 5 Chain length: 20 The pattern on the face has been achieved using a technique called electro etching. This technique uses a chemical bath coupled with electricity to cut the design into the metal. It is then treated with a solution that creates a darkened patina to bring out the details in the pattern.