Valentin

"This Roger de la Fontaine, he used to get pretty close to the gas. Could well be where he hid it, our fragment."

Description
Valentin is a Franco Miner, one of the many inhabitants on the Island of the Francos. Just like all the other Francos on the island, Valentin is searching for their lost Key Fragment. He uses a dowsing pendulum to find it.

Role in Twinsen's adventure
Valentin gave Twinsen a clue, that the fragment might be buried near the gas.