Barytolamprophyllite – [Ba2Na3(Fe3+, Ti4+)3(Si2O7)2(O,OH,F)4]

Barytolamprophyllite is the barium analog to lamprophyllite. It is a rare mineral at MSH.

PHYSICAL CHARACTERISTICS:

 

  • Color varies from pale yellow, orange, orange-yellow to
    brownish yellow.
  • Luster is vitreous to waxy or dull.
  • Diaphaneity is translucent to opaque.
  • Crystal System is monoclinic; C2/m.
  • Crystal Habits include fine fibrous, foliated thin strips to 2mm
    in length forming compact spheres, as sharp randomly oriented
    bladed crystals to 4mm and embedded blades and prisms to
    1.2cm in length.
  • Cleavage {100} is perfect.
  • Fracture is uneven.
  • Hardness is 2 – 3.
  • Specific Gravity is approximately 3.4 g/cm3.
  • Streak is pale brown to yellowish.
  • Associated Minerals include aegirine, albite, eudialyte, fluorite,
    nepheline, pectolite, sodalite and villiaumite.
  • Distinguishing Features: Crystal habit and luster.
  • Origin: Named in 1965 for its composition reflecting its barium
    content and similarity to lamprophyllite.

 

 

Dana class # 56.2.6c.1 – Sorosilicates: isolated tetrahedral noncyclic groups, N > 1; Si2O7 with additional O, OH, F, and H2O; lamprophyllite group
Strunz class # VIII/C.13-40 – Silicates; sorosilicates with [Si2O7]6-, with anions unfamiliar to tetraheders [O,OH,F]; rosenbuschite – lamprophyllite – hejtmanite series