Brianite

Brianite
Small white microcrystals of brianite from the Dayton meteorite
General
CategoryPhosphate minerals
Formula
(repeating unit)
Na2CaMg(PO4)2
IMA symbolBne[1]
Strunz classification8.AC.30
Crystal systemMonoclinic
Crystal classPrismatic (2/m)
(same H-M symbol)
Space groupP21/a
Unit cella = 13.36 Å, b = 5.23 Å,
c = 9.13 Å, β = 91.2°; Z = 4
Identification
ColorColorless
Crystal habitAnhedral grains with lamellar structure visible under polarized light
TwinningPolysynthetic on {100}
Mohs scale hardness4-5
LusterVitreous
DiaphaneityTransparent
Specific gravity3.0-3.1
Optical propertiesbiaxial (-)
Refractive indexnα = 1.598, nβ = 1.605, nγ = 1.608
Birefringence0.010
2V angle63° to 65°
Extinction2 to 3° from lamellae
References[2][3][4][5]

Brianite is a phosphate mineral with the chemical formula Na2CaMg(PO4)2.[4] It was first identified in an iron meteorite.[3] This mineral is named after Brian Harold Mason (1917–2009), a pioneer in meteoritics.[3]

It was first reported from the Dayton meteorite in Montgomery County, Ohio in 1966.[3] It occurs in phosphate nodules within the meteorite. Associated minerals include: panethite, whitlockite, albite, enstatite, schreibersite, kamacite, taenite, graphite, sphalerite and troilite.[5]

  1. ^ Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine. 85 (3): 291–320. Bibcode:2021MinM...85..291W. doi:10.1180/mgm.2021.43. S2CID 235729616.
  2. ^ Mineralienatlas
  3. ^ a b c d Brianite mineral information and data on Mindat
  4. ^ a b Brianite data on Webmin
  5. ^ a b "Brianite data from the Handbook of Mineralogy" (PDF). Archived from the original (PDF) on 2015-09-24. Retrieved 2015-01-31.