How to distinguish between granite and gneiss and sandstone
Sandstone: is a rock, with a layer of mineral composition of quartz-based, visible quartz was a grain of grinding phenomenon, the grain between the clay, iron, siliceous and other cemented, mica mostly light fragments , The general content is small, and there is a tendency to focus on the layers, sometimes sandstone can also see different rock composition, grinding garden better gravel, such as gravel content and more transition to conglomerate.
Gneiss: Similar to granite, mica or other dark minerals are often uneven band (or layered) distribution, and feldspar formation of eyeballs produced in the band, the mineral orientation is relatively strong, which is typical "Gneissed" structure for deep metamorphic rocks.
Granite: the main mineral composition of feldspar, quartz and mica, feldspar mica semi-self-shaped, quartz it shape, mineral distribution is more uniform, mineral orientation is not strong, sometimes visible thick feldspar porphyry. Different origin or period Of the granite mineral particle size can be a large difference for the formation of acidic magma cooling.
