Here's why:

* Semiconductor: Germanium is a semiconductor, meaning it has a conductivity between that of a conductor (like copper) and an insulator (like rubber). This means it can conduct heat, but not as well as metals.

* Thermal Conductivity: Its thermal conductivity is around 59 W/(m·K), which is significantly higher than many other non-metals.

For comparison:

* Copper: 401 W/(m·K)

* Aluminum: 237 W/(m·K)

* Silicon: 148 W/(m·K)

Applications:

Germanium's thermal conductivity makes it useful in applications like:

* Transistors and diodes: These components rely on heat dissipation for efficient operation.

* Infrared detectors: Germanium is used in infrared optics due to its good heat transmission.

* Heat sinks: Some specialized heat sinks use germanium to enhance heat dissipation.

However, it's important to note that Germanium is not as good a conductor as metals like copper or aluminum. It's generally used in applications where its conductivity is sufficient and its other properties, like its semiconducting nature, are advantageous.