Mention the effects of rock texture on weathering

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Texture is the relationship between the mineral grains that form a rock.two types of texture are significant for weathering:-
1)Crystalline texture:-such textured rocks are weathering resistant,generally.It has high resistance to stress,shows a large range of elastic behaviour and has low porosity(example:-0.1% in case of granite).a variety of it is the poikilitic texture,Which occurs when  a large crystal completely encloses one or more smaller crystals within it.
2)Sedimentary texture:-This is particularly important because sedimentary rocks underlie 80% of continental surface.Here,the component particles do'nt show interlocking characteristics.
Grain size affects the amount and potential activity of the water through it's relationship with sorting,porosity and surface area.a high porosity suggests large water content.A large surface area implies an extensive interface between the water and the grain and so enhanced chemical weathering.Water availability will influence  the percentage  of filled pore spaces  and the extent of water-grain contact.However,this depends on 2 internal factors of degree of void linkage  and presence of cementing minerals.there  are also relationships  between  grain size  with both permeability and capillarity.In nature particles are rarely perfectly sorted and smaller grains typically occupy empty spaces among the larger grains.so,over all sorting may be low and porosity poor.

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