Stones containing Silver Ore are salvageable items in Endless Ocean 2. They are made of stone, metal and high-density materials, as is shown to the player when one of these items is scanned using the Multisensor.
"A rock with high silver content. Silver is one of the most highly prized precious metals in the world."
The appraisal reward for discovering a single chunk of this material is two-hundred and twenty pelagos.