arkose

[ ahr-kohs ]

noun

1. a granular sedimentary rock composed of quartz and feldspar or mica; a feldspathic sandstone.

arkose

/ ˈɑːkəʊs /

noun

1. a sandstone consisting of grains of feldspar and quartz cemented by a mixture of quartz and clay minerals

arkose

/ är′kōs /

1. A usually pinkish or red sandstone consisting primarily of quartz and feldspar. Arkose usually forms as the result of the rapid disintegration of granite in areas of vigorous erosion. Its grains are usually angular and poorly sorted (mixed randomly in differing sizes).

Other Words From

• ar·kosic adjective

Word History and Origins

Origin of arkose¹

Borrowed into English from French around 1830–40

Word History and Origins

Origin of arkose¹

C19: from French

Example Sentences

Its heavy concentration of feldspar grains — known as arkose — means the rock is inevitably prone to chemical decay.

From Washington Post

Although Uluru appears to be shades of earthy red, depending on the time of day, it is a gray sedimentary rock called arkose.

From Washington Post

The sediments were subsequently buried and compressed to form harder rocks – called arkose and conglomerate by geologists.

From The Guardian

In early years as ing�nieur des mines he investigated and described various new minerals; he proceeded afterwards to the study of rocks, devising new methods for their determination, and giving particular descriptions of melaphyre, arkose, porphyry, syenite, &c.

From Project Gutenberg

At the base there is often an arkose, composed largely of fragments of serpentine and granite derived from the ancient floor.

From Project Gutenberg