https://wserv3.esc.cam.ac.uk/p1acollections/items/browse?collection=4&page=7&output=atom <![CDATA[1A Collections]]> 2024-04-09T21:21:59+01:00 Omeka https://wserv3.esc.cam.ac.uk/p1acollections/items/show/207 <![CDATA[<h2>Hardness</h2>]]> 2019-07-04T09:53:09+01:00

Title

Hardness

Subject

Hardness is measured on the Mohs scale. A hard mineral is rigid, resistant to pressure and is not easily scratched. Determining the hardness (or relative hardness) of a mineral in hand specimen can aid your identification of the mineral.
]]> https://wserv3.esc.cam.ac.uk/p1acollections/items/show/206 <![CDATA[<h2>Habit (or form)</h2>]]> 2019-07-04T09:53:08+01:00

Title

Habit (or form)

Subject

The three dimensional shape of a crystal. The crystal structure of a mineral influences the characteristic habit(s) which it displays. For example, biotite mica tends to display a platy or tabular habit because its crystal lattice is made up of sheets.
]]> https://wserv3.esc.cam.ac.uk/p1acollections/items/show/205 <![CDATA[<h2>Groundmass</h2>]]> 2019-07-04T09:53:08+01:00

Title

Groundmass

Subject

Rapidly cooled magmas are largely made-up of many tiny crystals. These make up the groundmass.
]]> https://wserv3.esc.cam.ac.uk/p1acollections/items/show/204 <![CDATA[<h2>Graphic texture</h2>]]> 2019-07-04T09:53:08+01:00

Title

Graphic texture

Subject

The regular intergrowth of two minerals (usually quartz and feldspar), which crystallised simultaneously. It is called “graphic” because the intergrowths resemble writing.
]]> https://wserv3.esc.cam.ac.uk/p1acollections/items/show/203 <![CDATA[<h2>Granular (or phaneritic)</h2>]]> Have a look at the hornblende biotite granite (L102) in the 1A Reference Series.]]> 2019-07-04T09:53:07+01:00

Title

Granular (or phaneritic)

Subject

This texture refers to an igneous or metamorphic rock which consists entirely of interlocking, roughly equant grains, large enough to be seen with naked eye.

Description

Have a look at the hornblende biotite granite (L102) in the 1A Reference Series.
]]> https://wserv3.esc.cam.ac.uk/p1acollections/items/show/202 <![CDATA[<h2>Glomeroporphyritic</h2>]]> 2019-07-04T09:53:07+01:00

Title

Glomeroporphyritic

Subject

This is an igneous texture in which phenocrysts clump together, within a fine-grained groundmass.
]]> https://wserv3.esc.cam.ac.uk/p1acollections/items/show/201 <![CDATA[<h2>Glomerocryst</h2>]]> 2019-07-04T09:53:07+01:00

Title

Glomerocryst

Subject

A glomerocryst is a clump of phenocrysts. A rock in which clumping of phenocrysts is abundant and pervasive is said to have a glomeroporphyritic texture.
]]> https://wserv3.esc.cam.ac.uk/p1acollections/items/show/200 <![CDATA[<h2>Glass</h2>]]> Have a look at the rhyolite glass (L113) in the 1A Reference Series.]]> 2019-07-04T09:53:07+01:00

Title

Glass

Subject

When magma is quenched (cooled exceedingly rapidly) even very small crystals are unable to grow. Instead, a volcanic glass is formed. It is amorphous (having no crystalline structure), and is consequently isotropic.

Description

Have a look at the rhyolite glass (L113) in the 1A Reference Series.
]]> https://wserv3.esc.cam.ac.uk/p1acollections/items/show/199 <![CDATA[<h2>Form</h2>]]> See habit.]]> 2019-07-04T09:53:07+01:00

Title

Form

Description

See habit.
]]> https://wserv3.esc.cam.ac.uk/p1acollections/items/show/198 <![CDATA[<h2>Foliation</h2>]]> 2019-07-04T09:53:06+01:00

Title

Foliation

Subject

This refers to any pervasive planar feature in a rock. It is produced by the arrangement of the constituent grains into sheet-like structures, usually in compositionally distinct layers. Foliations can be primary (e.g. bedding, fissility, flow banding) or secondary (e.g. cleavage).
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