Beryl – [Be3Al2Si6O18]

Beryl occurs very rarely at Mont Saint-Hilaire. It is very similar to fluorapatite in the hornfels environment, from which it is difficult to distinguish visually.

PHYSICAL CHARACTERISTICS:

 

  • Color is usually pale yellow to yellowish-green.
  • Luster is vitreous.
  • Diaphaneity is transparent.
  • Crystal System is hexagonal; P6/mcc.
  • Crystal Habits include hexagonal prisms terminated by the
    {0001} pinacoid and small pyramidal faces.
  • Cleavage {001} is indistinct.
  • Fracture is uneven to subconchoidal.
  • Hardness is 7.5 – 8.
  • Specific Gravity is approximately 2.6 g/cm3.
  • Streak is white.
  • Associated Minerals include albite, ancylite, chlorite group,
    molybdenite, siderite and UK #56.
  • Distinguishing Features: Crystal habit.
  • Origin: Known since antiquity, name comes from the Greek
    beryllos, an ancient term for a blue-green gem.

 

 

Dana class # 61.1.1.1 – Cyclosilicates; six-membered rings; beryl-cordierite group
Strunz class # VIII/E.12-10 – Silicates; cyclosilicates, six rings [Si6O18]12-; beryl series