The dripping water deposited minerals and built up the cavern decorations from the ceiling and floor.

When water did overflow and wash down the sides of the canal, it evaporated and deposited minerals along the base.

These basalt then underwent weathering by fluids, which deposited minerals enriched in incompatible elements in their fissures and cracks.

Four hundred million years ago, California lay at the bottom of a large sea; underwater volcanoes deposited lava and minerals (including gold) onto the sea floor.

Since that time, it has deposited minerals which grow a tufa deposit at the rate of two inches per year.

Waters flowing over the limestone and chalk have deposited minerals, and created natural dams.

Water seeping through these cavities or vesicles deposited minerals including gemstones such as amethyst, agate, jasper and calcite.

"We have a good chance of catching the fluids in the act of depositing minerals," Dr. Gardner said.

Some 400 million years ago, California lay at the bottom of a large sea; underwater volcanoes deposited lava and minerals (including gold) onto the sea floor; sometimes enough that islands were created.

Outside coatings and cracks inside the rocks suggest water deposited minerals, maybe bromine compounds.