Moonmilk (Hydromagnesite)

Moonmilk deposits seen along the 90 Minute Tour of Lehman Caves.

NPS PHOTO Scott babinowich

 

Moonmilk:  The Healing Power of Caves
Moonmilk is a white formation that looks like powder when dry or cottage cheese when wet. There is a lot of it in the Rocky Road and on the ceiling in the Inscription Room. Moonmilk can be a combination of different (mostly carbonate) minerals. Some common minerals composing moonmilk are calcite, aragonite and hydromagnesite. Humans have used moonmilk as medicine to stop bleeding, induce a mother's milk, and for ulcers. There are several theories for the formation of moonmilk. One is that bacteria play a role in its origins. Another is that the moonmilk is deposited directly from water the same way other speleothems are, but for some reason the crystals never grow large or connected.