The most collectible pieces from Coro include the Duettes pins and the en tremblant floral pins. Some trembler pins were also Duettes pins, such as the Quivering Camellia, making them all the more valuable.
Coro was a jewelry-producing company that operated between 1901 through the 1970s. Their most collectible pieces were the Duettes produced from the 1930s to 1940s. These pins came in two interlocking sections that could be worn together or broken apart and worn separately. Some examples included a pair of horse heads and a pair of enameled owls.
Tremblers are another sought after pin where a small section of the pin was attached via a spring that made it tremble when the wearer moved. Tremblers were often flower pins.