Geographic Minerals

Becquerelite: Properties and Occurrence

Becquerelite: Properties and Occurrence

Becquerelite is a uranium mineral with the chemical formula: Ca(UO2)6O4(OH)6·8(H2O). It is a highly radioactive and interesting mineral. It is a secondary mineral which contains calcium and is a bright yellow color. It has a Mohs hardness of about 2. It was named after the French physicist Antoine Henri Becquerel (1852–1908), who discovered radioactivity in 1896. Becquerelite contains about 70% uranium.

It is mainly mined in Kasolo of former Zaire, in the present day the Democratic Republic of the Congo.

General Information

  • Category: Oxide mineral
  • Formula: Ca(UO2)6O4(OH)68(H2O)
  • Crystal system: Orthorhombic
  • Crystal class: Pyramidal (mm2).


Becquerelite forms beautiful lustrous yellow transparent crystals, generally too small to be appreciated except under a microscope. Becquerelite forms in oxidation zones of sedimentary uranium deposits and is occasionally found in pegmatites. It is often found in association with uraninite, as it is one of the weathering products of that mineral.

  • Color: Amber-yellow, golden to lemon-yellow, yellow-orange, brownish yellow
  • Crystal habit: Tabular prismatic striated crystals exhibiting pseudohexagonal outline; coatings and fine-grained aggregates
  • Cleavage: Perfect on {001}; imperfect on {101}, {010} and {110}
  • Tenacity: Brittle
  • Mohs scale hardness: 2.5
  • Lustre: Adamantine to greasy
  • Streak: Yellow
  • Diaphaneity: Transparent
  • Specific gravity: 5.09 – 5.2

Remember, this is a radioactive mineral and should be stored away from other minerals that are affected by radioactivity and human exposure should definitely be limited. However, note that radioactivity is relative: uranium is not very radioactive compared to most unstable isotopes.


Becquerelite is a rare mineral that occurs as a weathering product of uraninite in oxidized uranium deposits and can also be found, albeit rarely, in pegmatites. Localities include in the Democratic Republic of the Congo, Austria, England, France, the United States, Canada, and Australia, among a few others. Becquerelite is highly radioactive.


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