<![CDATA[1A Collections]]> https://wserv3.esc.cam.ac.uk/p1acollections/items/browse?tags=volatile&output=rss2 Tue, 09 Apr 2024 21:16:32 +0100 p1acollections@esc.cam.ac.uk (1A Collections) Zend_Feed http://blogs.law.harvard.edu/tech/rss <![CDATA[Fluorite]]> https://wserv3.esc.cam.ac.uk/p1acollections/items/show/67

Title

Fluorite

Description

Formula

CaF2

Structure

Non-silicate

Crystal System

Crystal system: cubic

Physical Properties

Colour in hand specimen: extremely variable: colourless, white, yellow, green, blue and purple most common
Cleavage: perfect octahedral, up to four visible at one time, breaks into dipyramids
Hardness: 4

Optical Properties

Colour in plane polarised light: colourless, pale green or pale violet
Pleochroism: none
Relief: low

Mineral Specimens

M560 Fluorite 
Derbyshire 
Cubic fluorite crystals 
Generally very variable; in this case white to purple 
Glassy lustre 
Hardness 4 
Octahedral cleavage

Mineral Name

fluorite
fluorite_1.jpg
fluorite_CS.jpg
]]> Mon, 17 Jun 2019 16:29:15 +0100 <![CDATA[Apatite]]> https://wserv3.esc.cam.ac.uk/p1acollections/items/show/66

Title

Apatite

Description

Formula

Ca5(PO4)3(OH,F,Cl)

Structure

Non-silicate

Crystal System

Crystal system: hexagonal (-)

Physical Properties

Colour in hand specimen: green, white, yellow, blue brown etc.
Hardness: 5

Optical Properties

Colour in plane polarised light: generally colourless
Pleochroism: weak to moderate in coloured varieties
Relief: moderate
Birefrinence: 0.001-0.007; first order greys
Extinction: straight
Form: commonly hexagonal in cross-section

Rock Specimens

L100 Alkali granite 
L101 Granite 
L120 Granodiorite 
L130 Andesite, porphyritic (porphyrite)

Mineral Name

apatite
apatite_CS.jpg
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