| Speleothem rock | |
 Moonmilk ostensibly created from Macromonas bipunctata in the cave Bergmilchkammer | |
| Composition | |
|---|---|
| Carbonates (e.g., calcite, aragonite, hydromagnesite, monohydrocalcite) | |
| Texture | Creamy, soft |
Moonmilk (sometimes called mondmilch, also known as montmilch or cave milk) is a white, creamy substance found inside limestone, dolomite, and possibly other types of caves. It is a precipitate from limestone comprising aggregates of fine crystals of varying composition, usually made of carbonates such as calcite, aragonite, hydromagnesite, and/or monohydrocalcite.