Connector / Ferrule Material
Ferrule material identifies the substance used for the connector part that holds and positions an optical fibre.
The ferrule belongs to the fibre termination, not the light-carrying core or the outer cable jacket. These parts can use different materials.
Connector / Ferrule Material — Optical Cable
In an optical audio cable, the termination positions the fibre at the connection so light can pass between the cable and the port. Ferrule material describes this construction detail; the connector format still determines whether the cable fits the equipment.
Compare ferrule material only when the same part is being described. A metal connector housing does not necessarily mean the internal ferrule is metal. Material alone does not quantify optical loss or connection precision, so use stated performance and compatibility information for those questions rather than inferring them from the finish.