Granite: R1802

Title: Granite: R1802
Description: Hand Sample: This is a overall light-colored rock with many different kinds of crystals embedded in its white matrix. The matrix of the rock is consisted of quartz (40%) and feldspar (20%).Other crystal observed are muscovite (about 15%), biotite (10%) and some amount (10%) of hornblende.

Thin Section: This is a holocrystalline rock. 40% of the crystals are quartz(1), we can identify it by its low birefringence color and undulatory extinction. 50% of the crystals are plagioclase(2),because it displays tartan plate and polysynthetic twin.There are also some (10%) muscovite(3) crystals,and its cleavage is somehow bended. There is a small feldspar crystal (4)that displays oscillatory zoning but was embayed. A little (>5%) hornblende(5) is also present.

Life History: The rock has been underground,slowly cooling for a long time. It experienced a sudden cooling due to the subduction refrigerator effect.

Location: Concord, New Hampshire
Creator: 8585
Mediator: Tamara Carley

Media: https://exhibits.lafayette.edu/geology/files/original/9f39596a4851ae282a320eff58bfb195.JPG; https://exhibits.lafayette.edu/geology/files/original/8ff0c718716d3db49747abab77165159.JPG; https://exhibits.lafayette.edu/geology/files/original/c376006c342936631500917d3241fd24.JPG; https://exhibits.lafayette.edu/geology/files/original/ef4a2665e7ad39e56d53fa3217e726a4.JPG; https://exhibits.lafayette.edu/geology/files/original/8130c3f25c151bc0f121264626049835.JPG; https://exhibits.lafayette.edu/geology/files/original/9361faae3b9f68a501cb5a1d45dc8104.JPG

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