plagioclase

As such it represents a plagioclase with less than 10% anorthite content.

In the example of plagioclase, there are three cases of substitution.

It is the sodium endmember of the plagioclase solid solution series.

Plagioclase is an abundant mineral in the Earth's crust.

Plagioclase is an important series of tectosilicate minerals within the feldspar family.

Anorthosites form in plutons and are composed mostly of plagioclase.

Rock formed entirely of plagioclase feldspar is known as anorthosite.

In the case that halloysite is formed from plagioclase it will not pass through intermediate stages.

It has been observed in thin section that baddeleyite forms within plagioclase grains.

Up to half of the rock is plagioclase feldspar with the rest being ferromagnesian minerals.

The intermediate members of the plagioclase group are very similar to each other and normally cannot be distinguished except by their optical properties.

Microprobe analysis showed that the plagioclase was very calcium-rich.

Plagioclase is also a major constituent of rock in the highlands of the Earth's moon.

Typical values of the relevant parameters are for olivine and for plagioclase.

Other rare varieties include troctolite which has a greater percentage of calcic plagioclase.

At greater depth plagioclase is unstable and is replaced by spinel.

The feldspar is a basic variety of plagioclase (anorthite or bytownite).

The mantle is made from glass, that partially devitrified into pyroxene and plagioclase.

The plagioclase phenocrysts occasionally reach a grain-size of 10 millimeters.

Phenocrysts are plagioclase and hornblende with a grain size of 5 to 8 millimeter.

The groundmass of these rocks is composed of plagioclase and quartz.

It can be found in igneous rocks containing potassium feldspar and plagioclase.

The main mineral is calcium rich plagioclase.

There are several named plagioclase feldspars that fall between albite and anorthite in the series.

Typical associated minerals present as large phenocrysts are members of the plagioclase feldspar solid solution series.