Several factors effect the rate of growth for cave formations. The temperature outside, which affects the rate in which plants decay in the soil (amount of carbon dioxide in the soil), and the amount of rainfall are the two most important factors. From year to year the growth rate may change, even from one formation to another in the same area of a cavern. Therefore, there is no definitive answer to the question "how fast do they grow?" However, a feasible growth rate for some formations might be 1 millimeter every 100 years.

Aragonite is a heavier and denser form of calcite. Some formations have been found to have alternating layers of calcite and aragonite. The purest form of calcite and aragonite deposits is clear to a translucent white. Most speleothems have a solid white appearance. When formations have hues of other colors such as red and green, it is due to other minerals and organic materials that were on the surface which dissolved and were brought in as part of the calcite solution.

Small, slightly separated areas of a larger cavern are referred to as grottos. The term grotto also refers to a highly decorated natural or artificial cave. In antiquity these natural caves were regarded as dwelling places of divinities.
The crystalline structure of speleothems can be very porous. This can be a problem if people touch them. The natural oils in our skin will rub onto the formation leaving a light coating of oil. While one touch has minimal effect, many deposits of oil over time prevent any further growth. When calcium solution runs over the formation it normally leaves a layer of calcite behind. However, the human oils create a coating that the calcite cannot cling to. In a sense, the formation is now dead. We can see this same effect when washing a car that is waxed - the water beads up and runs off. Whereas, when washing a car that is not waxed, water tends to cling to the car. It is very important that people do not touch any surface in a cavern. (See the People & Caverns "Conservation" lesson plan for an activity related to this subject)

All of the Sierra Nevada Recreation Corporation caverns (Boyden, Moaning, California and Black Chasm) are profusely decorated with aragonite and calcite speleothems.