Cave pearls, or oolites, grow in shallow pools like pearls in an oyster. Successive thin layers of calcite coat tiny seed grains. This collection is 5 kilometres inside a cave in Pang Mapha district of Mae Hong Son province, Thailand. Inside the cave, these rare wonders of nature are priceless, but if they are stolen by insensitive or greedy humans, they become worthless balls of stone. These oolites are particularly well formed and precious. Taken on kodachrome slide film, Nikon FM2, nikkor 55mm lens, tripod and flashes.