orthoclase

Enormous crystals of orthoclase were common, some over five feet in diameter.

Eighteen crystal forms have been identified; eleven of them coincide with those known for orthoclase.

The gem known as moonstone (see below) is largely composed of orthoclase.

Amazonite (sometimes called "Amazon stone") is a green variety of orthoclase feldspar.

It is a frequent associate of orthoclase.

It consists almost entirely of granodiorite with large crystals of orthoclase.

He was particularly proud of a large, tabular orthoclase with a bluish white sheen in two directions.

Microxenocrysts of orthoclase likely exist in andesite at Ring Mountain.

The presence of orthoclase indicates a petrogenetic difference with nepheline gabbros.

Moonstone is composed of two feldspar species, orthoclase and albite.

The largest documented single crystal of orthoclase was found in Ural mountains, Russia.

It consists chiefly of orthoclase feldspar with sometimes hornblende and mica.

The higher-temperature Polymorphism (materials science) of orthoclase is sanidine.

Typically the host grain is orthoclase or microcline, and the lamellae are albite.

Present as blocky, perthitic orthoclase with Or.

This structure is very similar to that of orthoclase and sanidine but differs in a couple of ways:

For example, orthoclase is typically feldspar from granite, while its modifications occur in lavas of similar composition.

This is largely because volcanic rocks are often rich in potassium bearing minerals such as orthoclase and decay easily.

Most intrusions of this age are heavily sheared orthoclase porphyroclastic granites.

The lower-temperature polymorph of orthoclase is microcline.

Higher than normal potassium favors the production of orthoclase, which is usually absent from most mafic igneous rocks.

Other parts more rich in volatiles have formed pegmatites featuring milky quartz and pink orthoclase.

They contain orthoclase.

The exterior of the egg is studded with 1,660 diamonds, and made from quartz, platinum, and orthoclase.

The feldspar ranges from bytownite to oligoclase, being usually a variety of labradorite; orthoclase is scarce.