Gummite is a yellow amorphous mixture of

uranium Uranium is a chemical element with the symbol U and atomic number 92. It is a silvery-grey metal in the actinide series of the periodic table. A uranium atom has 92 protons and 92 electrons, of which 6 are valence electrons. Uranium is weakly ...

minerals, oxides, silicates, and hydrates of

, derived from the alteration of

uraninite Uraninite, formerly pitchblende, is a radioactive, uranium-rich mineral and ore with a chemical composition that is largely UO2 but because of oxidation typically contains variable proportions of U3O8. Radioactive decay of the uranium caus ...

. It is named for its gum-like luster. The material has been known by various other names, mostly due to differences in sample origins, including: eliasite from ''Elias'' – the name of a mine at

Jáchymov Jáchymov (); german: Sankt Joachimsthal or ''Joachimsthal'') is a spa town in Karlovy Vary District in the Karlovy Vary Region of the Czech Republic. It has about 2,300 inhabitants. The historical core of the town from the 16th century is wel ...

, coracite – a variety from

Lake Superior Lake Superior in central North America is the largest freshwater lake in the world by surface areaThe Caspian Sea is the largest lake, but is saline, not freshwater. and the third-largest by volume, holding 10% of the world's surface fresh w ...

, pittinite, pechuran, urangummit, and uranogummite.

References

Gummite on Mindat.org
Uranium minerals {{mineral-stub