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Webster 1913 Edition

Noun.

[So called because it occurs in rounded or flattened pieces which look like gum.]

(Min.)

A yellow amorphous mineral, essentially a hydrated oxide of uranium derived from the alteration of uraninite.

Gummite

gummite ‎(countable and uncountable, plural gummites)

(mineralogy) A yellow, amorphous mineral, a mixture of oxides and silicates of uranium, formed by weathering of pitchblende.