ID: 
2329
Maker's Name: 
The Big Man
Dimensions: 
3.2 × 3.2 × 2.2 cm

Galena (Lead Sulphide) was popularly used in detectors of radio waves, both domestically and commercially, in the early 1900s and later.

Frequently considered the best of detector materials until the advent of commercially produced Germanium and Silicon point contact Diodes. Also readily available.