from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. A hydrated magnesium carbonate mineral with the chemical formula Mg5(CO3)4(OH)2.4H2O, used as a fire retardant.
from the GNU version of the Collaborative International Dictionary of English
- n. A hydrous carbonate of magnesia occurring in white, earthy, amorphous masses.
from The Century Dictionary and Cyclopedia
- n. A white native hydrous carbonate of magnesium, sometimes occurring in crystals, but more frequently amorphous, earthy, and chalklike.
hydro- + magnesite (Wiktionary)
Lechuguilla Cave is not only the deepest at 494m (1,604 feet) and longest at 193 km (121 miles), but contains the largest collection of hydromagnesite balloon-like formations, subaqueous helictite formations and calcite speleothems.