Mineral Information and Data:

Agrellite
NaCa2Si4O10F [CNMNC approved formula]

Named for Stuart O. Agrell, British mineralogist, Cambridge University.

IMA status : Approved Species 1973 (IMA1973-032)
CLASSIFICATION 
Dana
(8th edition) :
70.01.01.04  
  (70) Inosilicate Column or Tube Structures
  (70.01) with columnar silicate units
  (70.01.01) Litidionite group
  
Nickel-Strunz
(10th edition) :
09.DH.75
  (09) Silicates
  (09.D) Inosilicates* Structural terminology per Liebau (1985)
  (09.DH) with 4-periodic single chains, Si4O12
  
Crystal system: Triclinic System
Point group (H-M): 1 — pinacoidal
Unit cell: a = 7.759 Å, b = 18.946 Å, c = 6.986 Å, a = 89.88°, b = 116.65°, g = 94.32°
Crystal Habit: Elongated and flattened
  
Color: White to grayish or greenish white
Diaphaneity: Transparent to translucent
Luster: Vitreous, pearly on cleavage
Hardness (Mohs): 5.5
Measured Density: 2.902 g/cm3
Cleavage: 3; on {110}, {110} excellent, on {010} poor
Tenacity: No data
Streak: White
  
Geologic Setting: In pegmatite lenses and pods and in mafic gneisses in a regionally metamorphosed agpaitic alkalic rock complex (Villedieu Township, Canada).
Mineral Association: Hiortdahlite, mosandrite, miserite, britholite, vlasovite, calcite, fluorite, clinohumite, gittinsite, norbergite, zircon, biotite, phlogopite, galena (Villedieu Township, Canada); miserite, aegirine, eudialyte, quartz (Wausau, Wisconsin, USA)
  
Luminescent Properties: Fluoresces bright pink under LW UV and
duller pink under SW UV.

 

Agrellite
White to grey, prismatic crystals to 1cm
associated with pink eudialyte, britholite and arfvedsonite.
Origin: Kipawa alkaline complex, Villedieu Township,
Témiscamingue Co., Quebec, Canada (type locality)
Sample size: 5.5 x 4 x 2 cm
Photo: Tom Loomis

 

Agrellite
(zoom-in of above)

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