https://wserv3.esc.cam.ac.uk/p1acollections/items/browse?tags=uranium&output=atom <![CDATA[1A Collections]]> 2024-04-09T21:16:31+01:00 Omeka https://wserv3.esc.cam.ac.uk/p1acollections/items/show/43 <![CDATA[<h2>Zircon</h2>]]>

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

L100 Alkali granite

Mineral Name

zircon
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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

L100 Alkali granite

Mineral Name

zircon
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