Hurlbutite

Hurlbutite is named after Cornelius Searle Hurlbut, Jr. (1906– 2005), Professor of Mineralogy, Harvard University.

Hurlbutite forms stout transparent to translucent colourless to greenish white crystals. Some material from Newport, New Hampshire, USA has been fashioned into gems.
General Information
Chemical Formula
CaBe
 
2
(PO
 
4
)
 
2
Michael O’Donoghue, Gems, Sixth Edition (2006)
Photos of natural/un-cut material from mindat.org
Physical Properties of Hurlbutite
Mohs Hardness6
Michael O’Donoghue, Gems, Sixth Edition (2006)
Specific Gravity2.90
Michael O’Donoghue, Gems, Sixth Edition (2006)
TenacityBrittle
Anthony et al, Handbook of mineralogy (2001)
FractureConchoidal
Anthony et al, Handbook of mineralogy (2001)
Optical Properties of Hurlbutite
Refractive Index1.595 to 1.604
Michael O’Donoghue, Gems, Sixth Edition (2006) RI for the alpha, beta and gamma rays is 1.595, 1.601 and 1.604
Optical CharacterBiaxial/-
Michael O’Donoghue, Gems, Sixth Edition (2006)
Birefringence0.009
Michael O’Donoghue, Gems, Sixth Edition (2006)
Colour
Colour (General)Colourless to greenish white
Michael O’Donoghue, Gems, Sixth Edition (2006)
TransparencyTransparent,Translucent
Michael O’Donoghue, Gems, Sixth Edition (2006)
LustreVitreous,Greasy
Anthony et al, Handbook of mineralogy (2001)
Crystallography of Hurlbutite
Crystal SystemMonoclinic
Michael O’Donoghue, Gems, Sixth Edition (2006)
HabitStout prismatic crystals, to 2.5 cm; as spheres with a radial fibrous structure
Anthony et al, Handbook of mineralogy (2001)
Geological Environment
Where found:Occurs as a latestage mineral in complex granite pegmatites
Michael O’Donoghue, Gems, Sixth Edition (2006)
Further Information
Mineral information:Hurlbutite information at mindat.org
Significant Gem Localities
USA
 
  • New Hampshire
    • Sullivan Co.
      • Newport
Gems, Sixth Edition, Michael O’Donoghue, 2006, p. 418
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