Are large grains easily seen as fine grained?
The texture of a rock consists of it's grain or mineral crystal size, the arrangement of the grains or crystals, and the degree of uniformity of the grains or crystals. Examples of rock texture would be: * Coarse grained--visible crystals or grains as in granite. * Fine grained--small grains, invisible to the unaided eye as in shale. * Porphyritic--large visible crystals in a fine grained matrix as in granite porphyry. * Schistose--layers of flattened micaceous…
Granularity refers to the ratio of actual computation to the amount of communication required by a parallel system. A fine-grained system will do a small amount of computation before transferring data/results. A coarse-grained system will do a relatively large amount of computation before reporting back.
They are rocks formed from lava at or near the surface. Basalt is a typical fine-grained extrusive igneous rock, composed of mineral crystals that require magnification to see. The fine-grained texture is due to rapid solidification of the lava which leaves little time for large mineral crystal formation.