Mineral Information and Data:

Amblygonite
LiAlPO4F [CNMNC approved formula]

Named from the Greek amblys and goni for blunt and angle.

IMA status : Valid species (Pre-IMA 1818) Grandfathered
CLASSIFICATION 
Dana
(8th edition) :
41.05.08.01  
  (41) Anhydrous Phosphates Containing Hydroxyl or Halogen
  (41.05) where (A B)2 (XO4) Zq
  (41.05.08) Amblygonite Group
  
Nickel-Strunz
(10th edition) :
08.BB.05
  (08) Phosphates, Arsenates, Vanadates
  (08.B) Phosphates, etc. with Additional Anions, without H2O
  (08.BB) With only medium-sized cations, (OH, etc.):RO4 about 1:1
  
Crystal system: Triclinic System
Point group (H-M): 1 — pinacoidal
Unit cell: a = 5.15 Å, b = 7.22 Å, c = 5.06 Å, a = 114.0°, b = 98.6°, g = 67.3°
Crystal Habit: Crystals equant to short prismatic; usually large cleavable masses
Twinning: Common on {111}; on {110}; rare on {111}
  
Color: White to grayish white, also colourless, pink, tan, greenish, bluish
Diaphaneity: Transparent to translucent
Luster: Vitreous to greasy, pearly on cleavage
Hardness (Mohs): 5.5 to 6
Measured Density: 3.08 g/cm3
Cleavage: 4; {100} perfect, {110} good, {011} distinct, {001} imperfect
Tenacity: Brittle
Fracture: Uneven to subconchoidal
Streak: White
  
Geologic Setting: An uncommon accessory mineral in zoned granite pegmatites; in high-temperature
tin veins and greisens.
Mineral Association: Lacroixite, apatite, lithiophilite, spodumene, lepidolite, petalite, pollucite,
tourmaline (pegmatites); cassiterite, topaz, mica (greisens)
  
Synonyms/varieties: Hebronite
Other Properties: Gemstone Readily Available.
Comments: Amblygonite group. Series with montebrasite

 

Amblygonite
Origin: Telirio mine, Linopolis, Minas Gerais, Brazil
Sample size: left 4 x 4 x 3 cm
Photo: Tom Loomis

 

Amblygonite
Amblygonite on albite
Origin: Telirio mine, Linopolis, Minas Gerais, Brazil
Sample size: 5 x 3 x 2 cm
Photo: Tom Loomis

 

Amblygonite
(zoom-in of above)

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