https://wserv3.esc.cam.ac.uk/p1acollections/items/browse?page=23&sort_field=added&output=atom <![CDATA[1A Collections]]> 2024-04-09T21:25:39+01:00 Omeka https://wserv3.esc.cam.ac.uk/p1acollections/items/show/226 <![CDATA[<h2>Microcline twinning</h2>]]> See cross-hatched twins.]]> 2019-07-04T09:53:16+01:00

Title

Microcline twinning

Description

See cross-hatched twins.
]]> https://wserv3.esc.cam.ac.uk/p1acollections/items/show/227 <![CDATA[<h2>Microcrystalline</h2>]]>

Compare with cryptocrystalline.

]]> 2019-07-04T09:53:16+01:00

Title

Microcrystalline

Subject

Rocks with a crystalline structure in which the individual crystals cannot be identified by the naked eye, but are large enough to be identified using standard optical microscopy are described as microcrystalline.

Description

Compare with cryptocrystalline.

]]> https://wserv3.esc.cam.ac.uk/p1acollections/items/show/228 <![CDATA[<h2>Microperthite texture</h2>]]> Have a look at the alkali granite (L100) and the hornblende biotite granite (L102) in the 1A Reference Series.]]> 2019-07-04T09:53:17+01:00

Title

Microperthite texture

Subject

Parallel lamellae or trains of blebs of one mineral, all in the same optical orientation, are enclosed in a single “host” crystal of another mineral. This texture is generally attributed to solid-state exsolution of the daughter phase from the host.

Description

Have a look at the alkali granite (L100) and the hornblende biotite granite (L102) in the 1A Reference Series.
]]> https://wserv3.esc.cam.ac.uk/p1acollections/items/show/229 <![CDATA[<h2>Mohs scale</h2>]]> 2019-07-04T09:53:17+01:00

Title

Mohs scale

Subject

Mineral hardness is described using the Mohs scale. The scale runs from very soft at 0 up to very hard at 10. The positions of minerals are determined by their relative hardness. For example, quartz can scratch calcite, but calcite cannot scratch quartz. Thus quartz is harder than calcite.
]]> https://wserv3.esc.cam.ac.uk/p1acollections/items/show/230 <![CDATA[<h2>Ooid</h2>]]> Have a look at the oolitic ironstone (L361) and the oolitic limestone (L353) in the 1A Reference Series.]]> 2019-07-04T09:53:18+01:00

Title

Ooid

Subject

Sub-spherical sedimentary grains comprising a nucleus surrounded by concentric layers of carbonate precipitate. Ooids form abiogenically. They are sometimes referred to as ooliths.

Description

Have a look at the oolitic ironstone (L361) and the oolitic limestone (L353) in the 1A Reference Series.
]]> https://wserv3.esc.cam.ac.uk/p1acollections/items/show/231 <![CDATA[<h2>Orthosilicate</h2>]]> 2019-07-04T09:53:18+01:00

Title

Orthosilicate

Subject

Silicate minerals in which the SiO4 tetrahedra do not share oxygen atoms with one another are called orthosilicates, or island silicates. These minerals do not contain bridging oxygen atoms.
]]> https://wserv3.esc.cam.ac.uk/p1acollections/items/show/232 <![CDATA[<h2>Overgrowth</h2>]]> 2019-07-04T09:53:18+01:00

Title

Overgrowth

Subject

The crystallisation of one mineral on the surface of another, producing a rim or part of a rim.
]]> https://wserv3.esc.cam.ac.uk/p1acollections/items/show/233 <![CDATA[<h2>Pearly [lustre]</h2>]]> Have a look at the muscovite mica (M301, M302) in the 1A Reference Series.]]> 2019-07-04T09:53:19+01:00

Title

Pearly [lustre]

Subject

Unsurprisingly the quality and intensity of light reflected from minerals displaying “pearly” lustre is reminiscent of pearls. This effect is produced by the reflection of light from many thin, coplanar, transparent sheets within the mineral. Muscovite, for example, has pearly lustre.

Description

Have a look at the muscovite mica (M301, M302) in the 1A Reference Series.
]]> https://wserv3.esc.cam.ac.uk/p1acollections/items/show/234 <![CDATA[<h2>Permeability</h2>]]> Compare with porosity.]]> 2019-07-04T09:53:19+01:00

Title

Permeability

Subject

The ability of a material to allow fluids to pass through it. A permeable material contains an interconnected system of channels though which fluids can diffuse. An impermeable material does not allow fluids to diffuse through it, either because it has no porosity, or because its porosity is unconnected.

Description

Compare with porosity.
]]> https://wserv3.esc.cam.ac.uk/p1acollections/items/show/235 <![CDATA[<h2>Phaneritic</h2>]]> See granular.]]> 2019-07-04T09:53:19+01:00

Title

Phaneritic

Description

See granular.
]]>