Geophones come in all shapes and size. Here are some of the smaller examples. My thumb for scale :)
Two coils surround the geophone. The double coil reduces distortion.
The geophone’s magnet with my thumb for scale. Note the little bits of metal stuck to it. It is magnetic! In the background there is a geophone inside of a red 3D printed helmet that allows OSOP technicians to hold the geophone in place.
The spring is delicate (you can see I already all broke all three places where the spring connects to the geophone’s inertial mass.)
The spring that holds the inertial mass in suspension.
The copper coil that surrounds the geophone’s magnet.