- a mineral, hydrated sodium borate, Na2B4O7⋅4H2O, occurring in transparent colorless crystals: the principal source of boron compounds in the U.S.
- a light soft colourless or white mineral consisting of a hydrated sodium borate in monoclinic crystalline form: an important source of borax and other boron compounds. Formula: Na 2 B 4 O 7 .4H 2 O
