Bystromite - Occurrence, Properties, and Distribution

Bystromite was named after Dr. Anders Bystrom (1916–1956), a Swedish crystal chemist, who made a structural analysis of the synthetic compound.

Properties of Bystromite

The following are the key properties of bystromite:

• Cell Data
  • Space group: P42/mnm
  • a = 4.68
  • c = 9.21
  • Z = 2
• Crystal Data
  • Tetragonal.
  • Point group: 4/m2/m2/m.
  • In porous massive aggregates of submicroscopic particles.
  • Few grains show square or rectangular outlines under the electron microscope.
  • X-ray powder pattern: 3.32 (100), 2.57 (90), 1.73 (90), 4.19 (70), 2.34 (50), 4.63 (40), 2.96 (40).
• Chemical Composition

  Elements	Content 1	Content 2
  Sb2O5	89.05	90.37
  MgO	6.65	7.43
  H2O+	2.60	2.20
  CaO	1.44	-
  insol.	0.25	-
  H2O-	0.17	-
  Al2O3	0.08	-
  Fe2O3	0.03	-
  Total	100.27	[100.00]

• Optical Properties
  • Optical class: Uniaxial
  • n = 1.855–1.915
• Estimated Properties

  Electron density	Bulk density (electron density) = 5.08 g/cm3 note: Specific gravity of bystromite = 5.70 g/cm3
  Photoelectric	PEBystromite = 221.22 barns/electron U=PEBystromite x ρ electron density= 1,122.98 barns/cm3
  Fermion index	Fermion index = 0.0068075007 Boson index = 0.9931924993
  Radioactivity	Bystromite is not radioactive.

How to Identify Bystromite

Bystromite can be identified in the field by its blue color. The density of bystromite is 5.7 g/cm³ with a hardness of 7 – approximate to quartz.

Global Distribution

Bystromite is distributed mainly in the La Fortuna and San Jose mines, El Antimonio, 27 km southwest of Agua Prieta, Sonora, Mexico.

Occurrence of Bystromite and Useful Mineral Association

Bystromite occurs in quartz veins in an oxidized antimony deposit. It is often associated with minerals such as stibiconite and quartz.

References

• Bystromite - RruffProject Website-University of Arizona
• Bystromite - Webmineral