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Webster 1913 Edition

Noun.

(Min.)

Hydrous carbonate of bismuth, an earthy mineral of a dull white or yellowish color.

[Written also

bismuthite

bismuthyl ‎(uncountable)

(chemistry) Any tartrate in the form of a univalent radical, wherein only one replaceable hydrogen atom has been replaced by a base, causing it to have twice the amount of acid contained in a normal salt.