Clay

Clay is a fine-grained natural rock or soil material that combines one or more clay minerals with traces of metal oxides and organic matter. Clays are plastic due to their water content and become hard, brittle and non–plastic upon drying or firing. Geologic clay deposits are mostly composed of phyllosilicate minerals containing variable amounts of water trapped in the mineral structure. Depending on the content of the soil, clay can appear in various colours, from white to dull gray or brown to a deep orange-red.

Clays are distinguished from other fine-grained soils by differences in size and mineralogy. Silts, which are fine-grained soils that do not include clay minerals, tend to have larger particle sizes than clays. There is, however, some overlap in particle size and other physical properties, and many naturally occurring deposits include both silts and clay. The distinction between silt and clay varies by discipline. Geologists and soil scientists usually consider the separation to occur at a particle size of 2 µm (clays being finer than silts), sedimentologists often use 4–5 μm, and colloid chemists use 1 μm.Geotechnical engineers distinguish between silts and clays based on the plasticity properties of the soil, as measured by the soils' Atterberg limits. ISO 14688 grades clay particles as being smaller than 2 μm and silt particles as being larger.

Mythimna ferrago

Mythimna ferrago, the clay, is a moth of the family Noctuidae. It is distributed throughout Europe and is also found in Morocco, Algeria, Turkey, Asia Minor, Armenia, Syria, Turkestan, Israel, Lebanon, Iraq, Iran, Central Asia and the western parts of temperate North Asia. Also Tibet.

The forewings of this species vary from buffish to orangey brown, usually with a darker central line running longways down the wing, interrupted by a pale stigma. There are usually a few small dark spots in the basal area. The hindwings are dark grey with paler margins. The male is easily recognizable by a triangular area of black hair on the underside of the abdomen. The wingspan is 36–44 mm. This moth flies at night in July and August and is attracted to light and sugar.

Technical Description and variation

The wingspan is 36–44 mm. Forewing pale greyish rufous, speckled with dark;lines indistinct, dark grey; the outer regularly lunulate-dentate, the teeth marked by black dashes on veins;reniform stigma obscure, ending in a cloudy pale spot at lower end of cell; hindwing greyish ochreous; ventral tufts black. The species varies in coloration: ferrago F. is the reddest form: - grisea Haw, is grey without any rufous admixture, with the markings generally clearer; fulvescens Tutt is rare, with fulvous in the place of red; — ab. marginata Tutt has silvery grey hindwings with broad dark border.

Clay (short story)

"Clay" is a short story by James Joyce published in his 1914 collection Dubliners.

The story