Allanite

Big Photo

Brazil
3.47 carats
© irocks.com

Allanite is named in 1810 after Thomas Allan, the Scottish mineralogist who first noticed it.

Allanite is a member of the Epidote group. It is opaque, with a dark brown (sometimes virtually black) colour.

Allanite contains the rare earth elements Yttrium and Lanthanum.

Allanite Gemstones by Colour

This table shows the variety of hues this gemstone can be found in. Click on a photo for more information.
 
Physical Properties of Allanite
Specific Gravity3.40 to 4.20
Roger Dedeyn, Tables of Gemstone Identification (2007)
Optical Properties of Allanite
Refractive Index1.64 to 1.828
Roger Dedeyn, Tables of Gemstone Identification (2007)
Birefringence0.013 to 0.036
Roger Dedeyn, Tables of Gemstone Identification (2007)
Colour
Colour (General)Brown
http://minerals.caltech.edu (2012)
Causes of ColourColored by iron and radiation damage and possibly by rare earth elements
http://minerals.caltech.edu (2012)
Further Information
Mineral information:Allanite information at mindat.org
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