His Dark Materials
His Dark Materials

The lodestone resonator was a communication device used by the Gallivespians to communicate with another such paired device across large distances or even between worlds. As a result, it was useful to spies. It was used by agents Chevalier Tialys and Lady Salmakia to report back to their leader, Lord Roke.[1] The paired devices of Tialys and Roke kept them in daily contact.[2]

Appearance and usage[]

The resonator was a dark grey stone of magnetic iron ore (a lodestone) like a short length of pencil on a stand of wood. It was operated by using a tiny bow whilst pressing points along the stone's surface, in a matter similar to playing a violin. These points were unmarked and, watching Tialys using the device, Lyra noticed that achieving the fluency to communicate with it required great skill and concentration. The state of mind needed was similar to that required when reading the alethiometer and, by extension, using the subtle knife.[3]

Tialys' lodestone resonator was stored in a wood case. It resembled a violin case scaled down to a size no longer than a walnut.[4] Wrapping wires around pegs on opposite ends of the stone allowed headphones to be used in receiving messages from the paired resonator. Message quality could be adjusted by changing the tension of the wire with the pegs.[3]

Tialys explained to Lyra that the devices worked by quantum entanglement. A lodestone's particles were entangled and then split into two to allow both parts to resonate together. Bowing one resonator would reproduce the sound exactly on the counterpart.[3]

The loadstone resonator did not work for Tialys in the world of the dead.[5]

Notable users[]

Behind the scenes[]

  • The loadstone resonator was used exclusively by Tialys. It is likely that Salmakia was not as skilled a user or was unable to operate the device at all. Her information to Lord Roke appears to have been communicated by her frequent meetings with Tialys.[1]
  • It is unknown whether Madame Oxentiel, Lord Roke's successor, was a user of the lodestone resonator.



  1. 1.0 1.1 The Amber Spyglass, Chapter 6
  2. The Amber Spyglass, Chapter 5
  3. 3.0 3.1 3.2 The Amber Spyglass, Chapter 14
  4. The Amber Spyglass, Chapter 13
  5. The Amber Spyglass, Chapter 22
  6. The Amber Spyglass, Chapter 9