Heinrichite

Autunite Group. Unstable at room temperature and dehydrates fairly rapidly to metaheinrichite (Walenta, 1965) which may be fully transparent. Most of the specimens shown on the photos here are probably metaheinrichite.

History

Activities related to discovery and approval of the group members

Structural context

Heinrichite
Crystal System monoclinicCrystal Class prismaticSpace Group P2/c
a7.133—7.1548 (7.1439)
b7.134—7.144 (7.139)
c21.29—21.61 (21.45)
alpha90
beta104.171—105.88 (105.0255)
gamma90
volume1053.62—1059.18 (1056.4)

Based on 2 measurements

Chemical context

Stoichiometric formulas

Heinrichite
mindat.org
  • March 13, 2023Ba(UO2)2(AsO4)2·10H2O
IMA
  • March 13, 2023Ba(UO2)2(AsO4)2 · 10H2O
mineralogy.rocks
  • Aug. 30, 2022Ba(U6+O2)2(As5+O4)2·10H2O

Elements recorded on EPMA

1
As
1
Ba
1
H
1
O
1
U

Physical properties

Hardness
2.5