"...cave pearls. I'm not especially knowledgeable about the real cave pearls. I believe they are a calcium concretion."
Karen, cave pearls are beautiful formations of calcite and a most
fascinating subject. All natural, these calcite formations are
formed in a similar way that fresh and saltwater pearls are formed.
Cave pearls form in a concentric fashion in shallow pools of water
found in caves. The water must be calcite rich and be in constant
agitation for the pearls to form. This agitation is usually from
water flowing or dripping from the ceiling. Slowly, over thousands
of years, small amounts of calcium carbonate dissolved in the water
form over the sand or pebbles that are the seed for these pearls.
The flowing or dripping water replenishes the calcium carbonate to
form additional layers as the pearl grows. The result is a smooth,
round and brilliant cave pearl.
If you have never seen a cave pearl before, a picture awaits you at:
Caves and their formations have always intrigued me and I try to
visit and study caves whenever time permits.