Speleothem in Soreq Cave

A speleothem is a "secondary mineral deposit formed in a cave, typically in limestone or dolostone solutional caves".  

Translation: a rock formation made when water drips in a limestone cave (or dolostone solutional, whatever that means).  

This is a column formed when a stalactite and a stalagmite meet.  Speleothem is the generic term for all rock formations, therefore stalactites and stalagmites are both types of speleothems.  I took this picture in Soreq Cave, Israel.