According to Wikipedia image 17 is called a Stalagmite. Wikipedia states that Stalagmites should normally not be touched, since the rock buildup is formed by minerals precipitating out of the water solution onto the existing surface; skin oils can alter the surface tension where the mineral water clings or flows, thus affecting the growth of the formation. Oils and dirt (mud, clay) from human contact can also stain the formation and change its color permanently. 🧱😉 Lies, lies and more lies!!