"Will ye look at deese!” roars Clarky, kneeling beside a dried-up pool. Sweeny and I gather around. Inside the pool, illuminated by our headlamps, are cave pearls.
Cave pearls are formed when a drop of water from the ceiling hits the limestone floor and throws up a speck of rock. This grain is jostled in its little cup of stone every time a drop hits it. Over thousands of years, a solid, almost perfectly round calcite pearl is formed.