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Zircon
Title
Zircon
Subject
Zircon is a common accessory mineral of many igneous rocks. Pleochroic haloes are formed by damage to the crystal lattice of enclosing minerals by the radioactive decay of elements such as Th and U in zircon. These may be particularly noticeable in biotite grains in old granitic rocks.
Description
Formula
Zr[SiO4]
Structure
Orthosilicate
Crystal System
Crystal system: tetragonal (+)
Physical Properties
Colour in hand specimen: reddish brown, yellow, grey, green or colourless
Hardness: 7.5
Optical Properties
Colour in plane polarised light: colourless to pale brown
Pleochroism: very weak
Relief: high
Birefringence: 0.042-0.065; 3rd order green to 4th order green
Extinction: straight
Twinning: rare
Rock Specimens
Mineral Name
zircon
Citation
“Zircon,” 1A Collections, accessed April 9, 2024, https://wserv3.esc.cam.ac.uk/p1acollections/items/show/43.