Texture is defined as the size, shape and arrangement of the grains of crystals in a rock. Igneous rock can have different textures depending on different bases: On the basis of degree of crystallization: All of the minerals present in the rock may be distinctly crystallized and may be easily recognized by unaided eye or they may be very poorly crystallized or even glassy (i.e. non crystallized) Polycrystalline (Phaneric/ Phanerocrystalline) : When all the minerals are distinctly crystallized. Holohyaline (Aphanitic): when the component minerals are very fine in size and glassy or non-crystalline in character. Merocrystalline : intermediate type of texture i.e. some minerals are crystallized and others are of glassy characters. b ) On the basis of granularity: Granularity defines the grain size of rocks taking into account the average dimensions of different component minerals. The rock is described as: Coarse grained : If the average size of the minerals of the rock
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