4" Orange Calcite Formation - Fluorescent

Stalactites form when water, seeping through rock, reaches an opening such as a cave or tunnel. Once this mineral-rich water (calcite in this case) precipitates out of the rock wall/ceiling, it leaves behind a crystal as the precipitate builds with each drop of water.

Stalagmites are likely to form from this process as those drops land on a cave floor, since the drops from the ceiling will still contain high mineral content. As long as water keeps flowing, it will continue to precipitate into stalactites and stalagmites.